Monday
December 22, 2014

Posts by ANDREA


Total # Posts: 698

chemistry
isotope chromium -51 has a half life of 28 days. If the original sample had a mass of 28.0 grams, what mass of chromium -51 sample remains after 84 days?
December 11, 2014

Math
What is 8 and 2 over 20 minus 6 and 8 over 20 8 2 - 20 8=? 2=? 20=?
November 14, 2014

physics
a boom 4.7 meters,10000 kg, 20 degree angle, find torqe on the pivot i fond force=10000x9.81= 98100 N perpindiclar force = 33552 N torqe = 4.7x33552 = 167695 Nm i am told this is wrong
November 14, 2014

Pre-Calculus
I really need help on this question Simplify the expression by using a Double-Angle formula or a Half-Angle Formula cos^2 0/2-sin^2 0/2
November 12, 2014

math
A plane travels 1020 miles from New York City to Minneapolis in 3.3 hours. The return trip takes 2.75 hours. a. How many times faster is the return trip?
November 3, 2014

statistics
Suppose that in a large population the proportion of people that have a certain disease is 0.01. Use the Poisson approximation to find the probability that at least four people will have the disease in a group of 400 randomly selected people.
November 2, 2014

inequalities
Determine when the function f(x)=3x^3+4x^2-59x-13 is less than 7
October 13, 2014

Chemistry
How many liters of liquid nitrogen are produced when 360.0 L of nitrogen gas is liquified at 77.36 kl
October 9, 2014

Algebra
Perform the indicated operation or 6x/16+1/16
October 3, 2014

Pre-Calculus
Find a polynomial of degree 4 that has a integer coefficients and zeros 1,-1,2 and 1/2 (one half)?
September 14, 2014

Math
How many x-intercepts and how many local extrema does the polynomial P(x)= x(sqrt)3-4x have? How many x-intercepts and how many local extrema does the polynomial Q(x)=x^3-4x have? and If a>0, how many x-intercepts and how many local extrema does each of the polynomials P(x...
September 7, 2014

Biology
Plant -+ Deer --+ Tiger The first step in the energy chain that created the bonds of proteins in the tiger's muscle cells in the food chain shown above is the A. deer the tiger ate. B. plant the deer ate. C. photons the sun made. D. carbohydrates the plant made. I think it...
July 13, 2014

chemistry
Which one of these is NOT a mechanism of heat transfer Select one: a. Reflection b. Radiation c. Convection d. Conduction
June 22, 2014

chemistry
Which one of the following statements regarding ideal gas laws is FALSE? Select one: a. An ideal gas has an infinite heat capacity b. The macroscopic ideal gas equation is PV = nRT c. The temperature must always be measured in Kelvin (K) d. A single molecule of gas has kinetic...
June 22, 2014

English
Meredith- "I can't believe we graduated!" Sara- "Ugh high school why." Meredith- "Can you not." Sara- "Fine, I'm super excited and just can not wait!" Meredith- smirks "I know you're being sarcastic but lovely enthusiam...
May 4, 2014

English
What kind of dialogue should I write with this? Write an example of a very brief dialogue between at least 2 people who are talking about a recent event. The characters should be about your age(15).
May 4, 2014

english
I need help with some conversation examples! 1) Write an example of a conversation between at least 2 adults who are talking about the possibility of one of them getting a new promotion with their current company. 2) Write an example of a very brief dialogue between at least 2...
May 4, 2014

Chemistry
comparing and contrasting why is sodium hydrogen carbonate an effective antacid but sodium hydroxide is not?
April 27, 2014

Math
Brian's boat has a top speed of 9 miles per hour in still water. While traveling on a river at top speed, he went 10 miles upstream in the same amount of time he went 20 miles downstream. Find the rate of the river current.
April 14, 2014

Calculus
At what interval is e^(-5x^2) concave up? I know the second derivative is 100x^2*e^-5x^2-10*e^-5x^2 but I just can not figure this one out. Thank you for your help!
March 28, 2014

philosophy (john dewey)
The expected outcome or pattern of Developed Standards of "Rules of Conduct", "Moral Training" and "School Organizations" served to meet the national demands. What is the problem with this being upheld in our educational system?
March 1, 2014

math
Mr Tan has some amount of money. If he distributes equally to 2 persons, he left with $1. If he distributes equally to 3 persons, he left with $2. If he distributes equally to 4 persons, he left with $3. If he distributes equally to 5 persons, he left with $4. If he ...
February 13, 2014

statistics, math, college
if np >5 and nq>5 estimate P (fewer than 4) with n=13 p=0.4 by using normal distribution as an approximate to the binomial distribution if np <5 or nq< then state that the normal approximation is not suitable
February 11, 2014

statistics, math, college
assume that adults have I.Q scores that are normally distributed with a mean of 100 and a standard deviation 15. find p2 which is the IQ score seperating bottom 2% from the top 98%
February 11, 2014

statistics
The assets(in billions of dollars) of the four wealthiest people in a particular country are 43,25,21,15 assume that samples of size n=2 are randomly selected
February 10, 2014

geometry
v-2/81pir2h
February 2, 2014

chemistry
What will be the average density for a sample of metal with a mass of 12.6 g and volume calculations of 7.8 mL and 8.3 cm3 ? Omit units in the answer and report answer to one decimal place.
January 22, 2014

chemistry
What will be the average density for a sample of metal with a mass of 12.6 g and volume calculations of 7.8 mL and 8.3 cm3 ? Omit units in the answer and report answer to one decimal place.
January 22, 2014

Math
A 6 ft man stands by a 30 ft tower and casts a 10 ft shadow. How long is the shadow cast by the tower and what time is it?
December 16, 2013

Math
A 6 ft man stands by a 30 ft tower and casts a 10 ft shadow. How long is the shadow cast by the tower and what time is it?
December 16, 2013

math
How many nickels and dimes does it take to make $1.95
December 10, 2013

math
370.9090900909090909909090909
December 9, 2013

Half-life
After two hours, 1/16 of the initial amount of a radioactive isotope remains undecayed. What is the half-life of the isotope?
November 18, 2013

algebra
thank you I'll check back with my teacher.
November 13, 2013

algebra
Sorry about the signs. The answer was suppose to be 2 seconds. That's what I'm not understanding. I'm coming out with what you have- I moved over the 2 and that left the t^2 = 39/2 but that doesn't come out to be two seconds which is suppose to be the answer
November 13, 2013

algebra
I'm stuck with this problem. h = -16t^2 + 312 the "t" is seconds after object released and h stands for height. We're suppose to set the equation to 0 so far this is what I have: -16t^2 + 312 = 0 -8(2t^2+39)= 0 -8=0 can be disqualified but how do I factor out...
November 13, 2013

physics
A ball is released from a hot air balloon moving downward with a velocity of -10.0 meters/second and a height of 1,000 meters. How long did it take the ball to reach the surface of Earth? Given: g = -9.8 meters/second2.
November 5, 2013

physics
A ball is released from a hot air balloon moving downward with a velocity of -10.0 meters/second and a height of 1,000 meters. How long did it take the ball to reach the surface of Earth? Given: g = -9.8 meters/second2.
November 5, 2013

physics
A ball is released from a hot air balloon moving downward with a velocity of -10.0 meters/second and a height of 1,000 meters. How long did it take the ball to reach the surface of Earth? Given: g = -9.8 meters/second2.
November 5, 2013

maths
Mr john has 350 layers, on the average, each hen lays two eggs per day.how many eggs will he expect after six days?
November 3, 2013

Statistics
356 hours
October 19, 2013

math
Everett made 3/5 of the baskets he shot. Suppose he shot 60 baskets. How many did he make?
September 17, 2013

math
There is something wrong with this definition for a pair of vertical angles: “If AB and CD intersect at point P, then APC and BPD are a pair of vertical angles.” Sketch a counterexample to show why it is not correct. Can you add a phrase to correct it?
September 15, 2013

Math
The Product of 2 consecutive odd numbers is 783. What are the numbers?
August 19, 2013

math
Steve the answer according to my book is 147
August 19, 2013

math
Assume the average height and weight of a female in your math class is 5'5" and 140 pounds. Use this information to write a variation equation then use it to find the weight of the female below if they had the same body type as the average female. Round answer to the ...
August 19, 2013

Math
If I went to the bank and fianaced $81,000 at 9% for 25 years what would my monthly principal and interest payment be?
July 17, 2013

world geography
As of 2008, the population of Australia was 21.3 million, and the population of New Zealand was closer to ________ million
June 22, 2013

Physics
A block of mass m1=1.6kg, initially moving to the right with a velocity of +4m/s on a frictionless horizontal track, colides with a massless spring attached to a second block of m2=2.1kg moving left with a velocity of -2.5m/s. The spring constant is 600 N/m. A) assuming the ...
June 5, 2013

math
2/3 + 3/5= 5/6 - 3/4= 3/5 X 2/5= 1/2 DIVIDE 5/8=
June 1, 2013

chemestry
polycarbonate has a density of 1.2 g/cm3. a photo frame is constructed from two 3.00mm of polycarbonate.Each sheet measures 28 cm by 22cm. what is the mass of the photo frame?
May 18, 2013

Physics
A ball is fastened to one en of a 28 cm string, and the other end is held fixed to a support. The ball whirls in a horizontal circle. Find the speed of the ball in its circular path if the string makes an angle of 35 degrees to the vertical.
May 16, 2013

Chemistry
Calculate the pressure exerted by a 14.6 mol NH3g in a 3.2 L container at -15.0 celcius using the Van der Waals equation.
May 15, 2013

chemistry
calculate the heat energy required to raise the temperature of a 500. gram iron pipe from 25 degress celcius to 100 degrees celcius. the specific heat for iron is .45 J/g degrees celcius
May 12, 2013

Biochemistry
what's transcription?
May 11, 2013

Biochemistry
what's transcription?
May 11, 2013

Biology
Consider the close-up view of a segment of DNA undergoing transcription from left to right. Transcription begins at and includes the G/C base pair shown in bold green type.
May 11, 2013

C/Justice
Inmate Code refers to the rules and values that have developed among prisoners inside prisons social systems.[1] The inmate code helps define an inmate's image as a model prisoner. The code helps to emphasize unity of prisoners against correctional workers. This code ...
May 9, 2013

Chemistry
Heating an ore of antimony (Sb2S3) in the presence of iron yields antimony and iron (II) sulfide. Sb2S3 + 3 Fe = 2Sb + 3 FeS When 15g of Sb2S3 reacts with 10g of Fe in the lab 9.84g of Sb is produced. What is the limiting reactant in this reaction? What is the theorectical ...
April 20, 2013

stat
A set of n = 5 pairs of X and Y values has SX = 10, SY = 20, and SXY = 10. For this set of scores, what is the value of SP?
April 18, 2013

science
How long does it take to prepare 4.00 g of Al by electrolysis of Al2O3 using a current of 2.50 ampere?
April 18, 2013

science
If 2.7 moles of copper metal was deposited from a solution of Cu(NO3)2, how many electrons were involved?
April 18, 2013

Physics
An electric force of 3x10^-8N is produced from an electrostatic point charge of 4x10^-10. It is 40cm from another electrostatic point charge. What is the charge of the second point?
April 11, 2013

Physics
If an electric force of 550N is produced from two charges, one is 345C, the other is 125C. How far apart are the charges?
April 11, 2013

math
A jara has 25 green grapes and 75 purple grapes. what is the probability that a purle grape will be chosen at random?
April 3, 2013

Physics
You are standing on a beach and 5 wave crests land on shore in 50 seconds. Each wave is 32m apart. Find Frequency, period, wavelength and speed.
April 2, 2013

math
Between which two consecutive integers is the value of this irrational number? square root of 117? A. 8 and 9 B. 10 and 11 C. 14 and 15 D. 20 and 21
April 2, 2013

math
Max,Owen,Elise, and Cara went to a school carnival. They each played the dart throw,ring toss,water shoot,and basketball throw. Each student won a different game. CLUES:*Max didn't score any points at the dart throw. * Elise correctly tossed 2 rings, but did not win the ...
April 2, 2013

math
Students submitted pictures for the school yearbook. Only 4/5 of the submitted pictures fit in the yearbook. There were 105 pictures that did not fit. Approximately how many total pictures were submitted for the yearbook? A. 105 B. 210 C. 420 D. 500
April 2, 2013

math
Emily,Zeke,Harry,& Brook each conducted surveys on the number of books people have in their homes. Then they answered the question below. "MUST ALL MEASURES OF CENTRAL TENDENCY APPEAR AS A NUMBER IN A SET OF DATA COLLECTED? A. Emily says this is always true because all ...
April 2, 2013

math
Which statement is true? A. All vertical lines have a slope of zero. B. All vertical lines have a slope positive slope. C. All vertical lines have a negative slope. D. All vertical lines have a undefined slope. WHY?
April 2, 2013

math
A box contains 4 red pencils, 3 blue pencils, and 3 yellow pencils. What is the probability that a student randomly selects a blue pencil, keeps it, then a second student randomly selects a yellow pencil? A. 1/10 B. 3/10 C. 6/10 D. 9/10
April 2, 2013

math
which shape will create tessellation using only translations? A. scalene triangle B. regular hexagon C. equilateral triangle D. isosceles trapezoid
April 2, 2013

Statistics
Weights of male mountain lions follow the normal distribution with a median of 150 lb and an interquartile range of 8.2 lb.  Find the 75th percentile of the weights. Find the 95th percentile of the weights.
March 28, 2013

Statistics
An orchestra consists of 25 members. The youngest member is 32 years old. She leaves and is replaced by a new member who is 30 years old. By how much does the replacement change the average age of the members of the orchestra? By how much does the replacement change the median...
March 28, 2013

Circles / Square
dude steave ur wrong the answer has to be a square root...
March 25, 2013

science
Who made the first light bulb?
March 21, 2013

Statistics
How do you find the intercept?
March 15, 2013

Statistics
That answer is incorrect.
March 15, 2013

Statistics
A large number of children were surveyed. The table below shows the distribution of the time they spent watching TV in the week before the survey. Intervals include the left endpoint but not the right. You can assume that the times are uniformly distributed within each ...
March 15, 2013

Statistics
Thanks I got it
March 15, 2013

Statistics
A class has 3 sections. Here is a summary of the scores on the final exam. Average SD Number of Students Section 1 68 9 20 Section 2 75 9 25 Section 3 60 9 32 Find the average score of all the students in the class.
March 15, 2013

Statistics
A large number of children were surveyed. The table below shows the distribution of the time they spent watching TV in the week before the survey. Intervals include the left endpoint but not the right. You can assume that the times are uniformly distributed within each ...
March 15, 2013

PHYSICS
Suppose that the magnetic field in the figure below has a magnitude of 1.1 T, the rod has a length of 0.86 m, and the hand keeps the rod moving to the right at a constant speed of 3.4 m/s. If the current in the circuit is 0.044 A, what is the average power being delivered to ...
March 14, 2013

chemistry
does Adding A increased Q, so the net reaction proceeds to the left to decrease Q. a+b=ab
March 11, 2013

chemistry
what mass of ammonium chloride is dissolved in 100 grams water in each of the following solutions in 1.10 molal NH4Cl solution, in a solution which is 75% water by mass in solution with a mole fraction of 0.15 NH4Cl? please help me solve this problem. thank you!
February 27, 2013

Economics
There are 10 identical consumers whose demand is D: p = 20 - 10q. There are 10 identical firms, each firm's marginal cost is MC(q)= 5 + 5q. The market is competitive. a) derive the market demand function b) derive the market supply function c) what is the market ...
February 4, 2013

Chemistry
how did you solve it???
January 19, 2013

math
5(3x+2)+2(3x+2)
January 13, 2013

english
how do you write a persuasive essay about youny adult women and teen girls quitting abortion.
January 6, 2013

math
Samantha opened a savings account and deposited some money into the account. The account pays an annual simple interest rate of 5%. After 9 years, the interest earned on the account was $1,800. How much money did Samantha deposit in the account?
December 30, 2012

English- edit my essay please?
The Great Gatsby Mortality is something we will all face at some point in our life. However, I doubt many people will deal with it in the same light as James Gatz did. He died once in his youth, at the age of seventeen, only to be reborn again as someone entirely new and ...
December 16, 2012

literary
What does my teacher mean by this? So I'm writing an essay on the great gatsby and I told my teacher about it via emai. (I'm doing online school) and this is what he told me... Also, make sure you develop the theme more than merely "mortality." I always tell ...
December 16, 2012

spanish III check?
I wasn't sure if the other question posted because I put all the sections into one question and I thought that might have been too much. I'm still not sure how to navigate this site correctly. I mean, I found this question of mine by going through all of the spanish ...
December 15, 2012

spanish III check?
1. En nuestra casa, mi hermana y yo preparamos la comida los fines de semana y _____ padres la preparan durante la semana.--- NUESTROS 2. Tiene que preparar mucha comida porque tengo cinco hermanos y mis hermanos pueden comerse un millón de enchiladas. ¡...
December 15, 2012

spanish III
check? I was unsure how to do this part... I still put the answers. Will you correct them if they are wrong and explain to me how to do it right? Thanks! Son las tijeras de nosotros. Son____________ tijeras.Son los gatos de la Sra. Barbosa.---- NOSOTROS Son____________ gatos....
December 15, 2012

spanish
I gave you everything my teacher gave me... Maybe that's why I'm so confused? Thank you for all your help though! It means a lot. I appriciate it!
December 15, 2012

spanish
thank you!!
December 15, 2012

spanish
I have the answers... will you tell me if theyre right?? Choose the correct form of the possessive adjective. Modelo: amigos (mi or mis) - mis - amigos is plural Libro- A. SU b. sus 2. Casas A. NUESTRAS b. nuestra 3. Cena a. sus B. SU 4. Sombrero A. TU b. tus 5. Guantes A. TUS...
December 15, 2012

algebra
At a crime scene, police officers find a murder victim in a tub full of warm water. A thermometer shows that the water temperature is 75 degrees F and the air temperature is 70 degrees F. It is known that most people fill a tub with water at 100 degrees F. Find Newton's ...
December 12, 2012

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