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September 5, 2015

Search: A sample of a radioactive substance decayed to 93.5% of its original amount after a year. (Round your answers to two decimal places.)

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calculus
A sample of a radioactive substance decayed to 94.5% of its original amount after a year. (Round your answers to two decimal places.) (a) What is the half-life of the substance? (b) How long would it take the sample to decay to 65% of its original amount?
November 9, 2012 by kela

Calc
A sample of a radioactive substance decayed to 93.5% of its original amount after a year. a) What is the half-life of the substance? ? years (b) How long would it take the sample to decay to 10% of its original amount? ? years
November 8, 2009 by Lee

MATH!
The mass of a radioactive substance follows an exponential decay model, with a decay rate of 5% per day. A sample of this radioactive substance was taken six days ago. If the sample has a mass of 3 kg today, find the initial mass of the sample. Round your answer to two decimal...
March 15, 2012 by Kim

calculus
The rate at which an amount of a radioactive substance decays is modeled by the differential equation dA/dt = kA, where A is the mass in grams, t is the time in years, and k is a constant. Answer the following. a) If a 100-gram sample of the radioactive substance decays to 95 ...
March 19, 2012 by ronnieday

Science
Radioactive substance decays so that after t years, the amount remaining, expressed as a percent of the original amount, is A(t)=100(1.6)^(-t). a) Determine the function A’, which represent the rate of decay of the substance. b) what is the half-life for this substance? c) ...
March 6, 2012 by jessica

Calculus-derivatives
Verify if these are correct answers. 1. The derivative of f(x)=e^2x -e^-2x is f'(x)=2e^2x - 2e^-2x? 2.A certain radioactive substance is decaying so that at time t, measured in years, the amount of the substance, in grams, given by the function f(x)=3e^-3t. What is the rate of...
March 6, 2012 by Matthew

math
round result to two decimal places...the answer i have is: 7.023 so two decimal places would it be: 702.0 You're asked to round to two decimal places. 7.023 = 7.02. Your answer has only one decimal place. so i guess my answer is wrong then...so what do they mean by two decimal...
July 15, 2007 by student

math
Phosphorus-32 (P-32) has a half-life of 14.2 days. If 200 g of this substance are present initially, find the amount Q(t) present after t days. (Round your growth constant to four decimal places.) How fast is the P-32 decaying when t = 21.5? (Round your answer to three decimal...
April 5, 2014 by Vanessa

Math
Phosphorus-32 (P-32) has a half-life of 14.2 days. If 200 g of this substance are present initially, find the amount Q(t) present after t days. (Round your growth constant to four decimal places.) How fast is the P-32 decaying when t = 21.5? (Round your answer to three decimal...
April 6, 2014 by Vanessa

math
Phosphorus-32 (P-32) has a half-life of 14.2 days. If 200 g of this substance are present initially, find the amount Q(t) present after t days. (Round your growth constant to four decimal places.) How fast is the P-32 decaying when t = 21.5? (Round your answer to three decimal...
April 7, 2014 by vanessa

Math
Phosphorus-32 (P-32) has a half-life of 14.2 days. If 200 g of this substance are present initially, find the amount Q(t) present after t days. (Round your growth constant to four decimal places.) How fast is the P-32 decaying when t = 21.5? (Round your answer to three decimal...
April 7, 2014 by Vanessa

Math
A radioactive substance decays according to the formula Q(t) = Q0e−kt where Q(t) denotes the amount of the substance present at time t (measured in years), Q0 denotes the amount of the substance present initially, and k (a positive constant) is the decay constant. (a) ...
April 5, 2014 by Vanessa

Math
A radioactive substance decays according to the formula Q(t) = Q0e−kt where Q(t) denotes the amount of the substance present at time t (measured in years), Q0 denotes the amount of the substance present initially, and k (a positive constant) is the decay constant. (a) ...
April 6, 2014 by Vanessa

pre calculus
32% of a particular radioactive substance disappears in 227 years. Part 1: Find the decay constant. Your answer must be correct to five decimal places. Part 2: Determine the time T in years required for 93% of the substance to disapper. Your answer must be correct to two ...
July 6, 2015 by Morgan

Algebra ASAP
Suppose that $17,000 is invested in a savings account paying 5.1% interest per year. (a) Write the formula for the amount A in the account after t years if interest is compounded monthly. A(t) = (b) Find the amount in the account after 3 years if interest is compounded daily...
August 3, 2015 by Fay

Pre-Calculus
At time t hours after taking the cough suppressant hydrocodone bitartrate, the amount A, in mg, remaining in the body is given by A=13(0.82)^t. a) What was the initial amount taken? b) What percent of the drug leaves the body each hour? c) How much of the drug is left in the ...
January 28, 2013 by Becky

college stats
Again sorry for all the questions. please help, I am not good at stats and find these questions very difficult. I would appreciate an explanation if possible. 1.What is the sample average? 2.What is the SD of the box? 3.What is the number of draws from the box (the sample size...
July 12, 2013 by penelope

Stats
Exercise 6-8 The Downtown Parking Authority of Tampa, Florida, reported the following information for a sample of 235 customers on the number of hours cars are parked and the amount they are charged. Number of Hours Frequency Amount Charged 1 18 $3 2 33 7 3 49 10 4 44 15 5 34 ...
September 28, 2010 by Nicole

Statistics
The Hill of Tara in Ireland is a place of great archaeological importance. This region has been occupied by people for more than 4,000 years. Geomagnetic surveys detect subsurface anomalies in the earth's magnetic field. These surveys have led to many significant ...
July 7, 2011 by ReeSha

statistics
Among 17 metal parts produced in a machine shop, 6 are defective. If a random sample of four of these metal parts is selected, find: (a) The probability that this sample will contain at least three defectives. (Do not round the intermediate answers. Round your answer to 4 ...
April 8, 2011 by Kate

Business Statistics
The Bureau of Labor Statistics’ American Time Use Survey showed that the amount of time spent using a computer for leisure varied greatly by age. Individuals age 75 and over averaged 0.30 hour (18 minutes) per day using a computer for leisure. Individuals ages 15 to 19 spend ...
May 5, 2015 by Kim

College Algebra
A radioactive substance decays in such a way that the amount of mass remaining after t days is given by the function m(t) = 9e−0.012t b) How much of the mass remains after 49 days? (Round your answer to one decimal place.)
July 31, 2015 by Melany

calculus
Carbon-14 is a radioactive substance produced in the Earth's atmosphere and then absorbed by plants and animals on the surface of the earth. It has a half-life (the time it takes for half the amount of a sample to decay) of approximately 5730 years. Using this known piece of ...
July 24, 2009 by j

Math/Calculus
After 5 days, a particular radioactive substance decays to 37% of its original amount. Find the half life of this substance. Is this right? Th= ln 2/ln(1/.37) x 5 days
October 17, 2011 by Christine

algebra
``If 18g of a radioactive substance are present initially and 5 yr later only 9 g remain, how much of the substance will be present after 11yr ? after 11yr there will be ___g of a radioactive substance. round the final answer to the nearest thousandth as needed. round all ...
December 1, 2014 by Ernie

algebra
A radioactive substance decays according to the formula A=A0e^kt where A0 is the initial amount of substance (in grams) A is the amount of substance(in grams) after t years k is a constant The half-life of the substance is 10 years.If we begin with 20g of the substance,how ...
April 3, 2015 by enhle

Calculus
a certain radioactive substance is decaying so that at time t, measured in years, the amount of the substance, in grams, is given by the function f(t)=3e^-3t. What is the rate of decay of the substance after half a year: I first found the derivative of f(t)=3e^-3t which is f'(...
February 14, 2015 by Sara

Calculus
The total worldwide box-office receipts for a long-running movie are approximated by the following function where T(x) is measured in millions of dollars and x is the number of years since the movie's release. T(x) = (120x^2)/(x^2 + 4) How fast are the total receipts changing ...
June 13, 2013 by Mike

Statistics
Information from the American Institute of Insurance indicates the mean amount of life insurance per household in the United States is $120,000. This distribution follows the normal distribution with a standard deviation of $38,000. (A) If we select a random sample of 58 ...
April 11, 2014 by Student5

Calculus
The percentage of alcohol in a person's bloodstream t hr after drinking 8 fluid oz of whiskey is given by the following equation. A(t) = 0.26te-0.3t , (0 t 12) (a) What is the percentage of alcohol in a person's bloodstream after 1/2 hr? After 6 hr? (Round your answers to four...
July 11, 2013 by Shan

business Maths
On September 20, Jody Jansen went to Sunshine Bank to borrow $3,900 at 5% interest. Jody plans to repay the loan on January 27. Assume the loan is on ordinary interest. (Use table value) (a) What interest will Jody owe on January 27? (Use 360 days a year. Do not round ...
April 23, 2012 by Ekanki

Chemistry
A radioactive sample contains 3.25 1018 atoms of a nuclide that decays at a rate of 3.4 1013 disintegrations per 26 min. (a) What percentage of the nuclide will have decayed after 159 d? % (b) How many atoms of the nuclide will remain in the sample? atoms (c) What is the half-...
April 16, 2010 by Trixie T

Algebra ASAP
The half-life of krypton-91 ^(91Kr) is 10 seconds. At time t = 0 a heavy canister contains 6 g of this radioactive gas. (a) Find a function m(t) = m02^−t/h that models the amount of ^(91)Kr remaining in the canister after t seconds. m(t) = (b) Find a function m(t) = m0e...
August 3, 2015 by Fay

Chemistry
How much a 2.00 g 239 Pu would have decayed after 1.6 x 10^4 years? The half-life for 239 Pu is 2.4 x 10^4 years. amount remaining= originalamount*(.5)^(1.6/2.4) amount decayed = original - amountremaining
November 26, 2006 by James

Algebra
5. The local soccer team won the championship a several years ago, and since then, ticket prices have been increasing $20 per year. The year they won the championship, tickets were $50. Write a recursive formula for a sequence that will model ticket prices. Is the sequence ...
April 16, 2015 by Sandra

algebra 1 sequences
Year 2003 2004 2005 2006 Populatation 22.12 22.49 22.86 23.41 A. divide the population for each year by the population in the preceeding year. Round to the two decimal places and show the Texas population increase that is approximately geometric. 1.01 B. Write the general term...
February 26, 2011 by amber

Alegbra sequences
Year 2003 2004 2005 2006 Populatation 22.12 22.49 22.86 23.41 A. divide the population for each year by the population in the preceeding year. Round to the two decimal places and show the Texas population increase that is approximately geometric. 1.01 B. Write the general term...
March 2, 2011 by Amber

math
Suppose that x is normally distributed with a mean of 10 and a standard deviation of 3. Find P(x ¡Ü 6). Note: Round your answer, if necessary, to two places after the decimal. Please express your answer with two places after the decimal.
March 16, 2013 by Keisha

Math
Can anybody show me step by step pls? A man invests $3000 in an account that pays 7.5% interest per year, compounded quarterly. 1. Find the amount after 3 years? (Round your answer to the nearest cent.) how much $? 2. How long will it take for the investment to double? (Round ...
August 10, 2015 by alice

Chemistry
1. Calculate the pH of a buffer solution that contains 0.32 M benzoic acid (C6H5CO2H) and 0.17 M sodium benzoate (C6H5COONa). [Ka = 6.5 × 10-5 for benzoic acid] Round your answer to two places past the decimal. 2. A solution is prepared by mixing 470 mL of 0.18 M Tris·Base and...
April 8, 2013 by Erin

Chemistry
1. Calculate the pH of a buffer solution that contains 0.32 M benzoic acid (C6H5CO2H) and 0.17 M sodium benzoate (C6H5COONa). [Ka = 6.5 × 10-5 for benzoic acid] Round your answer to two places past the decimal. 2. A solution is prepared by mixing 470 mL of 0.18 M Tris·Base and...
April 8, 2013 by Erin

statistics
Chicken Delight claims that 86 percent of its orders are delivered within 10 minutes of the time the order is placed. A sample of 70 orders revealed that 57 were delivered within the promised time. At the .02 significance level, can we conclude that less than 86 percent of the...
April 30, 2014 by wil

Math889
A particle moves according to a law of motion s = f(t), t ≥ 0, where t is measured in seconds and s in feet. f(t) = te−t/4 (a) Find the velocity at time t (in ft/s). v(t) = (b) What is the velocity after 1 s? (Round your answer to two decimal places.) v(1) = ft/s (...
October 13, 2014 by Anonymous

Stats
Suppose the following data are selected randomly from a population of normally distributed values. 42 51 43 48 41 57 54 39 45 48 45 39 46 Construct a 95% confidence interval to estimate the population mean. Round the intermediate values to 2 decimal places. Round your answers ...
December 19, 2013 by Tyler

statistics
A sample of n = 5 college students yielded the following observations on number of traffic citations for a moving violation during the previous year. Calculate s2 and s. (Round all answers to four decimal places.) s2 = 1 s = 2
September 14, 2010 by denise

stats
If a random sample of size n = 65 is drawn, find ¦̀x, ¦̉ x and P(24 ¡Ü x ¡Ü 26). (Round ¦̉ x to two decimal places and the probability to four decimal places.) ¦̀x = Correct: Your answer is correct.
March 3, 2014 by ruth

Physics
If a sample of a radioactive isotope has a half-life of 5 year(s), how much of the original sample will be left at the end of the second year? How much will be left at the end of the third year of thr original sample? How much will be left at the end of the fourth year of the ...
November 23, 2009 by TITA

Trigonometry
Find all solutions between 0 and 2pi. Round to two decimal places. In radians. Find all solutions between 0 and 2 pi. Round to two decimal places for the final solutions. The answers should be in radian mode. If you can use exact values use them. At least one of the 3 problems...
May 13, 2013 by Taylor B

finance
You want to have $2 million in real dollars in an account when you retire in 30 years. The nominal return on your investment is 8 percent and the inflation rate is 5.3 percent. What real amount must you deposit each year to achieve your goal? (Do not round intermediate ...
March 14, 2015 by jake

statistics
A sample of n = 9 has a mean of M = 72 with SS = 162. Use the sample to make a point estimate of ́ and to construct the 90% confidence interval for ́. (Round all answers to two decimal places ́ = ? ± ? ( ? ) The 90% confidence interval for ́: ( ? , ? )
November 4, 2011 by Anonymous

statistics
A sample of n = 9 has a mean of M = 72 with SS = 162. Use the sample to make a point estimate of ́ and to construct the 90% confidence interval for U. (Round all answers to two decimal places.) U = ? ± ? ( ?) The 90% confidence interval for U: ( ? , ? )
November 4, 2011 by Anonymous

algebra
You deposit $3000 in an account earning 7% interest compounded continuously. The amount of money in the account after years is given by A(t)=3000 e^(0.07 t) . How much will you have in the account in 5 years? $ Round your answer to 2 decimal places. How long will it be until ...
November 22, 2014 by christina

statistics
Over the past several months, an adult patient has been treated for tetany (severe muscle spasms). This condition is associated with an average total calcium level below 6 mg/dl. Recently, the patient's total calcium tests gave the following readings (in mg/dl). Assume that ...
April 11, 2015 by Interval Estimate

College Finance
1.A recent edition of The Wall Street Journal reported interest rates of 10.75 percent, 11.10 percent, 11.48 percent, and 11.75 percent for 3-, 4-, 5-, and 6-year Treasury security yields, respectively. According to the unbiased expectation theory of the term structure of ...
February 19, 2013 by Jona

QMB2100
Chicken Delight claims that 90 percent of its orders are delivered within 10 minutes of the time the order is placed. A sample of 70 orders revealed that 60 were delivered within the promised time. At the .02 significance level, can we conclude that less than 90 percent of ...
July 29, 2013 by Ariel

Calculus
Find the amount of an annuity if $210/month is paid into it for a period of 20 yr, earning interest at the rate of 8%/year compounded continuously. (Round your answer to two decimal places.)
July 17, 2013 by Anonymous

Calculus
Find the amount of an annuity if $210/month is paid into it for a period of 20 yr, earning interest at the rate of 8%/year compounded continuously. (Round your answer to two decimal places.) $
July 19, 2013 by Anonymous

personal finance
Hal Thomas wants to establish a savings fund from which a community organization could draw $800 a year for 20 years. If the account earns 3 percent, what amount would he have to deposit now to achieve this goal? (Round time value factors to 3 decimal places and final answer ...
February 6, 2015 by pat

calculus
In 1970, the total enrollment in public universities and colleges in a country was 5.1 million students. By 2004, enrollment had risen to 14.3 million students. Assume enrollment can be modeled by exponential growth. (a) Estimate the total enrollments in 1980, 1990, and 2000...
May 16, 2013 by jeff

statistic
A random sample of size n = 72 is taken from a finite population of size N = 644 with mean μ = 239 and variance σ2 = 325. Use Table 1. a-1. Is it necessary to apply the finite population correction factor? Yes No a-2. Calculate the expected value and the standard ...
February 5, 2015 by echo

math calculus (please help me)
In 1970, the total enrollment in public universities and colleges in a country was 5.1 million students. By 2004, enrollment had risen to 14.3 million students. Assume enrollment can be modeled by exponential growth. (a) Estimate the total enrollments in 1980, 1990, and 2000...
May 18, 2013 by jam

algebra
Two Questions: 1) A certain radioactive isotope has leaked into a small stream. 100 days later after the leak 10% of the original amount of the substance. Determine the half-life of this radioactive isotope. 2) During a research experiment, it was found that the number of ...
August 28, 2014 by kenni

college stats
Sorry for all the questions, I really need help and an explanation so I can fully understand. I really appreciate everything. Thank you. In a random sample of 519 judges, it was found that 285 had an introvert personality type. Construct a 95% confidence interval for the ...
July 12, 2013 by penelope

Urgent math
population growth model. Can anybody please help me out in trying to solve this problem? It's my homework and I don't seem to understand what I am getting. The count in a culture of bacteria was 400 after 2 hours and 25,600 after 6 hours. (a) What is the relative rate of ...
August 3, 2015 by Lydia

math
If a ball is thrown directly upward with a velocity of 14 m/s, its height (in meters) after t seconds is given by y = 14t − 4.9t2. What is the maximum height attained by the ball? (Round to two decimal places.) ______ m After how many seconds is that height attained? (...
August 14, 2014 by May

5 Pre-Calculus Questions
1. What is the value of x in the right triangle below? If needed, round your answer to two decimal places. 32 angle, 15 inches, find the x in base… 2. A 10-foot ladder is leaning up against the side of a building so that the top of the ladder reaches the top of the building. ...
June 30, 2011 by Anonymous

business Maths
On September 14, Jennifer Rick went to Park Bank to borrow $2,500 at interest. Jennifer plans to repay the loan on January 27. Assume the loan is on ordinary interest. Refer to Days in a year table. (a) What interest will Jennifer owe on January 27? (Use 360 days a year. Do ...
April 23, 2012 by Ekanki

Finance
If you put $10,000 at the end of each year into a savings account that pays interest at the rate of 5 percent a year, how much would you have after 4 years? Use the Appendix B. Round the answer to the nearest cent. Round FV-factor to three decimal places.
February 6, 2015 by Coulton

math ,correction
is this right? Find the standard deviation to the given data. The manager of a small dry cleaner employs six people. As part of their personnel file, she asked each one to record to the nearest one-tenth of a mile the distance they travel one way from home to work. THe six ...
July 13, 2007 by student

MATH
The value V of a machine t years after it is purchased is inversely proportional to the square root of t+2. The initial value of the machine is $10,000. Find the rate of depreciation when t=5 . Round your answer to two decimal places. A. -381.80 PER YEAR B. -1889.82 PER YEAR C...
September 19, 2011 by Roger

probability
In a recent survey, 35 percent indicated chocolate was their favorite flavor of ice cream. Suppose we select a sample of ten people and ask them to name their favorite flavor of ice cream. (b) What is the probability exactly four of those in the sample name chocolate? (Do not...
February 8, 2013 by Tonya

Finite Math
Find the effective rate of interest corresponding to a nominal rate of 6%/year compounded annually, semiannually, quarterly, and monthly. (Round your answers to two decimal places.)
May 6, 2011 by Dee

Math
The null and alternate hypotheses are: H0: π1 ≤ π2 H1: π1> π2 A sample of 100 observations from the first population indicated that X1 is 70. A sample of 150 observations from the second population revealed X2 to be 90. Use the .05 significance ...
July 24, 2012 by John

Calc
I am having trouble with these two problems for my Calc class. I have tried answering a few times already, but i keep getting it wrong. Help please and thank you. For the limit below, find values of δ that correspond to the ε values. lim_(x->1)(3 + x - 3x^3) = 1...
September 21, 2009 by Joe

calculus
please help me Asap In 1970, the total enrollment in public universities and colleges in a country was 5.1 million students. By 2004, enrollment had risen to 14.3 million students. Assume enrollment can be modeled by exponential growth. (a) Estimate the total enrollments in ...
May 16, 2013 by jeff

STATS
The fracture strength of a certain type of manufactured glass is normally distributed with a mean of 575 MPa with a standard deviation of 17 MPa. a) What is the probability that a randomly chosen sample of glass will break at less than 575 MPa?(Round your answer to 4 decimal ...
October 30, 2010 by Helen

statistics question
Thank you in advance for anyone able to help me with this... In a sample of 67 randomly selected students, 27 favored the amount being budgeted for next year's intramural and interscholastic sports. Construct a 98% confidence interval for the proportion of all students who ...
November 12, 2014 by linda

Math
say you have 4/13 and the decimal equivalent to it is 30.76923 how do I round 3 decimal places? you round 2 da thousandths. For example since the decimal u hav is 30.76923, round it to the last three numbers after the decimal point. So 30.76923 would be 30.769. It would remain...
May 31, 2007 by Amber

Applied Calculus
For its beef stew, Betty Moore Company uses aluminum containers that have the form of right circular cylinders. Find the radius and height of a container if it has a capacity of 29 in.3 and is constructed using the least amount of metal. (Round your answers to two decimal ...
April 2, 2013 by Jacob

business maths
a 18 year loan requires month ends payments of $587.69 including interest at 18.4% compounded monthly. what wil be the balance on the loan after half of the payments have been made. (do not round intermediate calculations, just round final answer to two decimal places)
November 3, 2014 by aiman

accounting
What would you pay for a $50,000 debenture bond that matures in 15 years and pays $5,000 a year in interest if you wanted to earn a yield of: (Round computations to 2 decimal places and use the rounded amounts to calculate the final answer. Round the final answer to 2 decimal ...
February 23, 2009 by joe

Accounting
What would you pay for a $50,000 debenture bond that matures in 15 years and pays $5,000 a year in interest if you wanted to earn a yield of: (Round computations to 2 decimal places and use the rounded amounts to calculate the final answer. Round the final answer to 2 decimal ...
September 29, 2010 by Scott

Business maths
calculate the amount that will be accumulated after 20 years if $1600 is invested at the beginning of every six months at 13.5% compounded semi annually. Do not round intermediate calculations, just round the final answer to 2 decimal places
November 3, 2014 by aiman

SCIENCE
We did a radioactive decay and half life lab with m&ms and I do not understand these conclusion questions: 1. how many half lives would it take for 500 nuclei to decay to 6.25% of the original number of nuclei? My ans: 3125?- do not think that's right! 2. Is there any way to ...
November 27, 2014 by Bethany

Finance
Due to a recession, expected inflation this year is only 2.75%. However, the inflation rate in Year 2 and thereafter is expected to be constant at some level above 2.75%. Assume that expectations theory holds and the real risk-free rate is r* = 3%. If the yield on 3-year ...
December 15, 2014 by Rokera

Math
Round off the answers to two decimal places. 535.71428571428 and 468. 75
September 22, 2010 by Bailey

Managerial Finance
Due to a recession, expected inflation this year is only 2%. However, the inflation rate in Year 2 and thereafter is expected to be constant at some level above 2%. Assume that expectations theory holds and the real risk-free rate is r* = 2.25%. If the yield on 3-year Treasury...
September 23, 2011 by SLW

Math/Finance
Due to a recession, expected inflation this year is only 2%. However, the inflation rate in Year 2 and thereafter is expected to be constant at some level above 2%. Assume that expectations theory holds and the real risk-free rate is r* = 2.25%. If the yield on 3-year Treasury...
September 24, 2011 by SLW

physics
If a radioactive isotope has a half-life of 1 year, how much of the original sample will be left at the end of the 2nd year?
August 23, 2012 by Anonymous

Calculus
If an open box has a square base and a volume of 106 in.3 and is constructed from a tin sheet, find the dimensions of the box, assuming a minimum amount of material is used in its construction. (Round your answers to two decimal places.) height in length in width in
April 4, 2011 by Josh

statistics
A film alliance used a random sample of 50 U.S. citizens to estimate that the typical American spent 78 hours watching videos and DVDs last year. The standard deviation of this sample was 9 hours. (a) Develop a 95 percent confidence interval for the population mean number of ...
April 24, 2013 by Anonymous

Science
if a radioactive isotope has a half-life of one year, how much of the original sample will be left at the end of the second year?
August 23, 2012 by aileen

Science
if a radioactive isotope has a half-life of one year, how much of the original sample will be left at the end of the second year?
August 23, 2012 by aileen

calculus
A common inhabitant of human intestines is the bacterium Escherichia coli. A cell of this bacterium in a nutrient-broth medium divides into two cells every 20 minutes. The initial population of a culture is 51 cells. (a) Find the relative growth rate. (Assume t is measured in ...
November 9, 2012 by kela

Applied Calculus
If an open box has a square base and a volume of 112 in.3 and is constructed from a tin sheet, find the dimensions of the box, assuming a minimum amount of material is used in its construction. (Round your answers to two decimal places.) Height: Length: Width:
March 12, 2013 by Jacob

math calculus
The marginal cost of a product is modeled by dC/dx= 16/cube root 16x + 3 where x is the number of units. When x = 17, C = 120. (a) Find the cost function. (Round your constant term to two decimal places.) c= (b) Find the cost of producing 90 units. (Round your answer to two ...
May 28, 2013 by steven

math calculus (please help me)
The marginal cost of a product is modeled by dC/dx= 16/cube root 16x + 3 where x is the number of units. When x = 17, C = 120. (a) Find the cost function. (Round your constant term to two decimal places.) c= (b) Find the cost of producing 90 units. (Round your answer to two ...
May 28, 2013 by abc

Statistics
30 randomly selected cans of Coke are measured for the amount of cola in ounces. The sample values have a mean of 12.18 ounces and a standard deviation of 0.118 ounces. The 99% confidence interval is ( ounces, ounces). Round each result to two decimal places.
November 9, 2013 by Katie

calc
The price in dollars of a house during a period of mild inflation is described by the formula P(t)=94000 e0.03 t, where t is the number of years after 1990. Answer the following questions: B. In the year 2000 the value will be increasing at a rate of dollars per year. (Round ...
February 22, 2013 by Hannah

math
The price in dollars of a house during a period of mild inflation is described by the formula P(t)=94000 e0.03 t, where t is the number of years after 1990. Answer the following questions: B. In the year 2000 the value will be increasing at a rate of dollars per year. (Round ...
February 22, 2013 by Hannah

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