A certain material decays at a rate of 1.9% per year. The sample is 260 grams. How much will be left in 11 years?
67,704 results

Exponential and Logarithmic functions
A certain material decays at a rate of 1.9% per year. The sample is 260 grams. How much will be left in 11 years? How long will it take to have only a 100g sample left? 
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 100gram sample of the radioactive substance decays to 95 ... 
algebra
Suppose a sample of Cesium137 with initial mass of 200 grams decays to a mass of 160 grams voer the course of 10 years. Find the halflife of Cesium137 (Round to the nearest year) How much Cesium137 is left in the sample after 60 years? Round to the nearest tenth of a gram. 
AP Calculus
An Initial amount of 100 grams of Thorium234 decays according to the model: dP/dt=0.02828P (where t is measured in years). a) Find the equation for the amount of Thorium left after t years. b) Determine the halflife of this radioactive isotope c) How long will it take for ... 
Physics/Math
A 25.0 gram piece of charcoal is found in some ruins of an ancient city. The sample shows a 14C activity, R, of 250 decays/min. How long (in years) has the tree this charcoal came from been dead? I think I have the use the equation: R=lamda*No*e^(lamda*t) but I am not sure ... 
Calculus
A certain radioactive material decays exponetially. The percent, P, of the material left after t years is given by P(t)= 100(1.2)^t a)Determine the half life of the substance 
Pre Calculus
If a 25 mg sample of radioactive material decays to 18.4 mg in 5 years, how long will it take the sample to decay to 20.5 mg? 
math
Suppose strontium90 decays at a rate of 2 percent per year. (a) Write the fraction P of strontium remaining, as function of t, measured in years. (Assume that at time t=0 there is 100 % remaining.) Answer: P(t)=(.98)^t (b) Estimate the halflife of strontium. (c) If presently... 
College algebra
Sample of 500gms radioactive substance decays according to the function A(t)5000.044t where t is the time in years. How much of the substance will be left in the sample after 20 years?round to the nearest whole gram 
College Algebra
The halflife of a radioactive material is about 34.6 years. How much of a 1gram sample of the material is left after 30 years? 
science
As redioactive material decays and the percentage of new material in the original sample increases, does the age of the sample substance increase, decrease, or remain the same? 
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 halflife of the substance is 10 years.If we begin with 20g of the substance,how ... 
Math
A radioactive material has a half life of 500 years. A) Given 20 grams of this material, how much will remain after 1,000 years? B) Given 100 grams of this material, how much will remain after 750 years? Thank you to whom ever can help me :) 
Math
Suppose strontium90 decays at a rate of 2 percent per year. (a) Write the fraction P of strontium remaining, as function of t, measured in years. (Assume that at time t=0 there is 100 % remaining.) Answer: P(t) = (b) Estimate the halflife of strontium. Answer: Hint: Use your... 
calculus
Suppose strontium90 decays at a rate of 2 percent per year. (a) Write the fraction P of strontium remaining, as function of t, measured in years. (Assume that at time t=0 there is 100 % remaining.) Answer: P(t) = (b) Estimate the halflife of strontium. Answer: Hint: Use your... 
NEED HELP WITH CALC
Suppose strontium90 decays at a rate of 2 percent per year. (a) Write the fraction P of strontium remaining, as function of t, measured in years. (Assume that at time t=0 there is 100 % remaining.) Answer: P(t) = (b) Estimate the halflife of strontium. Answer: Hint: Use your... 
Chemistry
It took 109.8 years for a 300.0 mg sample of an unknown radioactive material to completely disintegrate. Calculate the mass of the element (in grams/mole) assuming that the disintegrations per second are constant over the lifetime of the sample, and the sample is labeled 100.... 
Physics
A gram of living plant material with Carbon14 , decays at a rate of about 16 disintegrations per minute. When the plant dies, the Carbon14 decays, with a halflife of 5600 years. A gram of the dead plant is found to decay at about 1 disintegration per minute. Calculate the ... 
Math  Exponential Decay
Radium decays exponentially. Its halflife is 1,690 years. How long will it take for a 50gram sample of radium to be reduced to 5 grams? 1/2P = Pe^(1690k) (ln1/2)/(1690) = k 4 x 10^4 = k 5 = 50e^kt ln0.1 = kt ln0.1/k = t 5,630 years = t ...but textbook answer is 5,614 ... 
precalc
I am really struggling with a bunch of problems. Any help with any of the following would be greatly appreciated. Thanks 1. ln e^(ln x)  ln(x  3) = ln 8 2.3e^(6x  2) = 18 The word problems, especially, are killing me. 3. In the formula A = Iekt, A is the amount of ... 
science
A substance has a halflife of 10,000 years and an initial mass of 1,000 grams. How many years will pass before only 250 grams of the substance's parent material is left? 
FINANCE 200
You receive $5000 three years from now. The discount rate is 8 percent. What is the value of your investment two years from now? (Multiply 5000 by .926 (one year discount rate at 8%) Will it be worth $9,260? 
algebra 2
In the formula A(t) = A0ekt, A is the amount of radioactive material remaining from an initial amount A0 at a given time t, and k is a negative constant determined by the nature of the material. An artifact is discovered at a certain site. If it has 72% of the carbon14 it ... 
Algebra please check my answers
1) The linear function f(x) contains the points (10, 29) and (2, 83). If g(x) = 25x  50, which statement is true? A. The functions f(x) and g(x) both have positive slopes. <<< B. The functions f(x) and g(x) both have negative slopes. C. The function f(x) has a ... 
Science
If 15% of the radioactive material decays in 5 days, what would be the percentage of amount of original material left after 25 days? 
AlgebraProblems
Please help with my word problems? Solve the problem. The rabbit population in a forest area grows at the rate of 6% monthly. If there are 260 rabbits in April, find how many rabbits (rounded to the nearest whole number) should be expected by next April. Use y=260(2.7)^0.06t... 
Pre Calculus
Tritium, a radioactive isotope of hydrogen, has a halflife of 12.4 years. Of an initial sample of 69 grams, how much will remain after 75 years? a. 1.5848 grams b. 61.5289 grams c. 0.0000 grams d. 1.0426 grams e. 17.2500 grams 
Environmental Science 11th grade
If half of a quantity of radioactive material decays in 10 years, in another 10 years? 
Word ProblemsMath
Please help with my word problems? Solve the problem. The rabbit population in a forest area grows at the rate of 6% monthly. If there are 260 rabbits in April, find how many rabbits (rounded to the nearest whole number) should be expected by next April. Use y=260(2.7)^0.06t... 
Algebra I
A sample of radioactive material weighing 45 grams has a decay rate of 4.25% each day. The equation y = 45(2.7)–0.0425t can be used to find the amount of material that still remains, where t is the number of days that have passed. Approximately what is the amount of material... 
Physics
If a sample of a radioactive isotope has a halflife 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 ... 
fin
The following tabulation gives earnings per share figures for the Foust Company during the preceding 10 years. The firm’s common stock, 7.8 million shares outstanding, is now (1/1/03) selling for $65 per share, and the expected dividend at the end of the current year (2003) ... 
Physics!
The activity of a sample of 35(upper#) 16(lower#)Sulfer (T 1/2= 7.55x10^6 s) is 2.51x10^5 decays per second. WHat is the mass of the sample? m= in grams PLease help me out...Thank you! :) 
Physics
The activity of a sample of 35(upper#) 16(lower#)Sulfer (T 1/2= 7.55x10^6 s) is 2.51x10^5 decays per second. WHat is the mass of the sample? m= in grams PLease help me out...Thank you! :) 
Physics Plz help me
The activity of a sample of 35(upper#) 16(lower#)Sulfer (T 1/2= 7.55x10^6 s) is 2.51x10^5 decays per second. WHat is the mass of the sample? m= in grams PLease help me out...Thank you! :) 
Physics Plz help me
The activity of a sample of 35(upper#) 16(lower#)Sulfer (T 1/2= 7.55x10^6 s) is 2.51x10^5 decays per second. WHat is the mass of the sample? m= in grams PLease help me out...Thank you! :) 
Math
Suppose you wnat to purchase a house for 650,000. Hoe much of the loan would be left after 10 years if the interest rate was 3.8 % and it was a thirty year mortgage? And if you made the montly payments for ten years, and then increase your payment to 4000 per year, how many ... 
Physical Science
A gram of radioactive material has a halflife of one year. After four years how much radioactive material will be left...0g, 1/2g, or 1/4g? None of the above. The answer onehalf to the fourth power. 
Chemistry  Isotopes
The isotope caesium 137 has a half life of 30 years. How long will it take for the amount of this isotope in a sample of caesium to decay to one sixteenth of its original amount? Please can someone explain how I can calculate this from the quantities that have been stated? ... 
chem
the following procedure may be used to determine the density of a granular material. A sample of a granular material weighing 4.35 grams is placed in a 15 mL flask and then completely filled with benzene (liquid) the density of which is .879g/cc. The granular material and ... 
calculating annuity
IF a company will generate 80,000 in annual revenue each year for the next eight years and the interest rate is 8.2% what is the present value of the savings? An EXCEL spreadsheet will be helpful for these types of calculations. Let S1 be savings in year 1, S2 in year 2, and ... 
Pre Calculus
Exponential growth and decay find the half life of a radioactive substance if 220 grams of the substance decays to 200 grams in 4 years? 
Epidemiology
Age (Years) Influenza / Pneumonia Deaths (Di) 20072011 Population (Pi) from 20072011 (2009 used as midyear) <1 year 7 53,267 14 years 4 207,832 514 years 5 468,548 1524 years 14 447,580 2534 years 27 440,646 3544 years 40 325,022 4554 years 92 305,929 5564 years ... 
Science
A material has 32 atoms in all; 24 decayed and the rest undecayed. If the halflife of the radioactive material is 1000 years, what is the age of the material? a. 1000 years b. 2000 years c. 3000 years d. 4000 years 
algebra
Julie has 250 grams of a radioactive substance. The substance decays every hour. How long will it take until she has 20 grams of the substance left? 
Math
How do I solve this if there is no equation to this 1. The population of the bacteria in a Petri dish increases by a factor of 10 every 10 hour. If there are initally 20 bacteria in the dish, how long will it take before the population increases to 60,000 to the nearest tenth ... 
PreCalculus
It is well known that superman can withstand as much as 3 grams of Green Kryptonite indefinitely. However, exposure to more than 3 grams for more than 13 hours is fatal. Assume that Kryptonite decays at an hourly rate of 5.35% If superman is trapped in a room with 6 grams of ... 
Calculus
Suppose strontium90 decays at a rate of 2 percent per year. (a) Write the fraction P of strontium remaining, as function of t, measured in years. (Assume that at time t=0 there is 100 % remaining.) Answer: P(t)=? 
Science/Chemistry
22Na has a halflife of 951 days. How many grams of a 1.00 kg sample would be left after 4 years? 
Physics Help Please
archaeologist digging at the site of an ancient settlement discover the remains of a wooden structure. carbon 14 dating of the wood from the structure finds a decay rate of 180 decays/min. Knowing that the decay rate for living wood is 600 decays/min and the decay constant for... 
chemistry
Calculate the residence time of sodium in millions of years if the total amount of sodium in the oceans is 1.5 x 10 to the 22 grams, and is supplied to the ocean at a rate of 2.2 x 10 to the 14 grams per year. 
Algebra 1
The function A = A0e0.01386x models the amount in pounds of a particular radioactive material stored in a concrete vault, where x is the number of years since the material was put into the vault. If 500 pounds of the material are initially put into the vault, how many pounds ... 
economics
Tom plans to gamble each year for the next 20 years, starting at at the end of year 1. If he loses 4.47 dollars in odd years (i.e., years 1, 3, 5, etc) and wins 7.46 dollars in even years (i.e., years 2,4, 6 etc), what will be Tom's (internal) rate of return per year from ... 
precalculus
The function A=A0e^(0.0099x) models the amount in pounds of a particular radioactive material stored in a concrete vault, where x is the number of years since the material was put into the vault. If 600 pounds of the material are initially put into the vault, how many pounds ... 
Physics Help Please! Decay Questions
archaeologist digging at the site of an ancient settlement discover the remains of a wooden structure. carbon 14 dating of the wood from the structure finds a decay rate of 180 decays/min. Knowing that the decay rate for living wood is 600 decays/min and the decay constant for... 
Pre Calculus 1
thirty percent of a radioactive substance decays in four years. assuming the decay is exponential, find the half life of the substance. the beginning of 1975 the population of a country was 40 million and growing at a rate of 3% per year. Assume that the growth is exponential... 
finance
Barbara wants to save money to meet 2 objectives: i. She would like to be able to retire 25 years from now and have a pension for 15 years after that.She would like to get the first annual payment on the pension 26 years from now, she would like it to be $30,000 and she would ... 
algebra
1) how many billions of years will it take 1000 grams of uranium238 to decay to just 125 grams? 2) a researcher had 37.5 g left from a 600 g sample of sulfer35. how many halflives passed during that time? 3) look at problem 2. how many days passed during that time? 
Physics: Fluids
A sample of an unknown material weighs 260 N in air and 175 N when immersed in alcohol of specific gravity 0.700. 
Finance
We are considering the introduction of a new product. Currently we are in the 34% tax bracket with a 15% discount rate. This project is expected to last five years and then, because this is somewhat of a fad project, it will be terminated. The following information describes ... 
math
Brenda earns $14,260 per year. paid 24 times a year with 1 exemption. If $19.63 in taxes is withheld from each check at what rate is she taxed 
science
If a radioactive isotope has a half life of 10 years and you start with 100 grams what is the fraction left, percentage left, and amount of original in grams I would like for you to explain how to do it not tell me the answer that's the question 
College Math
In a suburb, housing costs have been increasing at 5.2% per year compounded annually for the past 8 years. A house worth $260,000 now would have had what value 8 years ago? 
Math
You invest $7,000 in a twoyear CD. At the end of the 2 years, you receive $8,331.97. Assume you left the first year' s interest in the account, what was your yearly interest rate? 
Algebra
Jane agrees to buy a car for a down payment of $4000 and payments of $260 per month for 9 years. If the interest rate is 9% per year, compounded monthly, what is the actual purchase price of her car? (Round your answer to the nearest cent.) 
Help meee
Answer from spreadsheet Answer from hand calculation Problem #1: Find the total amount if you deposit $500 at a rate of 5% for two years using simple interest. Year 1 Year 2 Problem #2: Find the total amount if you deposit $300 at a rate of 6% for three years using simple ... 
math
Brenda Luai earns $14,260 per year. She is paid 24 times per year and claims 1 exemption. If $19.63 in taxes is withheld from each paycheck, at what rate is she taxed? 
Math
Please Help!!!! I do not understand and if someone could help that would be great! Thanks !! Problem #1: Find the total amount if you deposit $500 at a rate of 5% for two years using simple interest. Year 1 Year 2 Problem #2: Find the total amount if you deposit $300 at a rate... 
FIN200 FV, PV and Annuity Due CP
I just want to know if anyone can help me in determining if I am on track with this assignment and if anyone can point out where I am wrong and how I need to fix it. I have already completed this assignment on my own and need someone to review it. Thank You Here is the ... 
chemistry
Please help me through this problem... A 0.5117 gram fertilizer containing phsphorus was oven dried. The weight of the dried sample is 0.4998 grams. However, 10% moisture is still retained in the sample. Calculate the moisture content in the sample in as received and dry basis... 
math check
Brenda Luai earns $14,260 per year. She is paid 24 times per year and claims 1 exemption. If $19.63 in taxes is withheld from each paycheck, at what rate is she taxed? 
math algebra
The amount A, of 70 grams of a certain radioactive material remaining after t years can be found by the equation A=70(0.62)^t. When will 10 grams remain? 
pre calc
A 50 gram sample of radioactive strontium will decay to 32 grams in 18 years. a. Find an equation that will model how much of our sample M will remain after t years. 
Fin Management
David purchased a $100,000 participating whole life policy. The annual premium is $2,280. Projected dividends for the first 20 years are $15,624. The cash value after 20 years will be $35,260. If the premiums were invested at 5 percent for 20 years, the premiums would grow to... 
discrete math
You have borrowed $8000 from the bank. Suppose you want to repay a fixed amount of money for each of the following n years (except possibly the last year), and the annual interest rate r does not change in these n years. For example, if r = 10% and you repay $4000 each year, ... 
math: precalculus
You have 5 grams of carbon14; whose halflife is 5730 years. a)Write the rule of the function that gives the amount of carbon14 remaining after x years. b)How much carbon14 will be left after 4,000 years? c)When will there be just 1 gram left? 
FINANCE
8. Suppose that the current oneyear rate (oneyear spot rate) and expected oneyear Tbill rates over the following three years (i.e., years 2, 3, and 4, respectively) are as follows: 1R1 = 5 percent, E(2r1) = 6 percent, E(3r1) = 7.5 percent E(4r1) = 6.85 percent 
accounting
An amortizing bond is a bond which pays the principal not at its maturity, but prior to its maturity, according to some schedule, typically (but not necessarily) in equal amounts. In particular, consider a floatingrate amortizing bond, which pays 25% of its principal amount ... 
finance
You note the following yield curve in The Wall Street Journal. According to the unbiased expectations theory, what is the 1year forward rate for the period beginning one year from today, 2f1? (Round your answer to 2 decimal places.) Maturity Yield One day 2.50% One year 6.00 ... 
math  interest rates
Car loan: 5yr annualpayment loan with interest rate of 6% per year. Annual payment = $5,000. You have just made a payment and decided to pay the loan off by repaying the outstanding balance. a) what is payoff amount if you have owned the car for one year (so there are 4 ... 
Finance
EMAR expects to receive $2,000 per year for 10 years and $3,500 per year for the next 10 years. What is the present value of this 20year cash flow? Use an 7% discount rate. 
Chemistry H
60.0 grams of Th210 with a half life of 50,000 years is allowed to decay for 250,000 years. How much of the original quantity remains? In addition, Th210 decays via beta emission. Write the equation for its transmutation. 
Finance
Ambrin Corp. expects to receive $2,000 per year for 10 years and $3,500 per year for the next 10 years. What is the present value of this 20 year cash flow. Use a 11% discount rate. 
Finance
ABC corp. expects to receive $2000 per year for years and $3500 per year for the next 10 years. what is the percentage value of this 20 years cash flow? use an 7% discount rate 
Maths
ABC corp. expects to receive $2000 per year for years and $3500 per year for the next 10 years. what is the percentage value of this 20 years cash flow? use an 7% discount rate 
FINANCE
8. Suppose that the current oneyear rate (oneyear spot rate) and expected oneyear Tbill rates over the following three years (i.e., years 2, 3, and 4, respectively) are as follows: 1R1 = 5 percent, E(2r1) = 6 percent, E(3r1) = 7.5 percent E(4r1) = 6.85 percent Using the ... 
Math
You have just isolated a new radioactive element. If you can determine its halflife, you will win the Nobel Prize in physic. You purify a sample of 2 grams.One of you colleges steals half of it, and 3 days later you find that 0.1 grams of the radioactive material is still ... 
finance
The Blinkelman Corporation has just announced that it plans to introduce a new solar panel that will greatly reduce the cost of solar energy. As a result, analys now expect the company’s earnings, currently (year 0) $1 per share to grow by 50 percent per year for the next ... 
finance
The Blinkelman Corporation has just announced that it plans to introduce a new solar panel that will greatly reduce the cost of solar energy. As a result, analys now expect the companyâ€™s earnings, currently (year 0) $1 per share to grow by 50 percent per year for the ... 
Java Computer Science
So in math, a restriction can be set. For example 30<x<60. So I'm trying to do this in a Java else if statement. else if (x>30 && x<60) {, will that do the same thing. Because I did that in my program but I'm getting my desired output twice. I'm suspecting this is ... 
Chemistry
In 6.20 h a 100 g sample of ag 112 decays to 25 grams. what is the half life of ag 112. I think the answer is 3.10 but I'm not sure. Thanks in advance =) 
college algebra
Suppose that the Russian population is declining by 0.48% each year, and continues to decline at this rate every year. a.) what is the overall 'growth' factor (really a decline factor) for 40 years of population decline? As a percentage of the current population, what will the... 
Finance
Consider the following scenario: John buys a house for $150,000 and takes out a five year adjustable rate mortgage with a beginning rate of 6%. He makes annual payments rather than monthly payments. Unfortunately for John, interest rates go up by 1% for each of the five years ... 
Finance
Consider the following scenario: John buys a house for $150,000 and takes out a five year adjustable rate mortgage with a beginning rate of 6%. He makes annual payments rather than monthly payments. Unfortunately for John, interest rates go up by 1% for each of the five years ... 
PreCal
The population of Las Vegas, Nevada in 2000 was 478,000 and is increasing at the rate of 6.28% per year. At this rate, when will the population reach 1 million people? a)1.51 years b)2.32 years c)12.12 years d)10.84 years 
Math
Suppose that a certain material has a half life of 25 years, and there are A(t)=10(1/2)^t/25 grams remaining after t years. find: i) initial amount i) Amount after 80 years Solutions i) A(0)=10(1/2)^(0/25) =10(1/2)^0 =10(1) =10 ii)A(80)=10(1/2)^(80/25) =10(1/2)^(16/5) =10(0.... 
Maths
Can you help me with this? I don't know how to figure it out. the population growing at an annual rate r will triple in a time t given by the formula t = ln 3/r If the growth rate remains constant and equals 9% per year, how long will it take the population of the town to ... 
chemistry
an original sample of K40 has a mass of 25.00 grams. After 3.9x 10 to the ninth years, 3.125 grams of the original sample remains unchanged. What is the halflife ok K40 in minutes? Is it 6.8328 x 10 to the 14th 
Pre Calculus
17. population growing at an annual rate r will triple in a time t given by the formula t = ln 3/r If the growth rate remains constant and equals 9% per year, how long will it take the population of the town to triple? a. 6 . 6 years b. 1 years c. 5 . 3 years d. 2 . 2 years e... 
chemistry
a 15g sample of gold198 decays in 3g in 6 days. how much will be left after 8 days?