# math

the number of red marbles varies inversely as the square of the number of blue marbles. when there were four reds, there were 20 blues. How many reds would there be if there were only four blues?

1. 👍
2. 👎
3. 👁
1. 100

1. 👍
2. 👎
2. r = k/b^2 , r is red, b is blue

4 = k/400
k = 1600
then r = 1600/b^2

when b = 4
r = 1600/16
= 100

1. 👍
2. 👎

## Similar Questions

1. ### Math ~ Check Answers ~

1. There are 35 marbles in a bag: 9 blue marbles, 8 green marbles, 4 red marbles, 8 white marbles, and 6 yellow marbles. Find P (red). Write the probability as a fraction in simplest form, a decimal, and a percent. a.) 4/31,

2. ### Math

A bag contains 9 red marbles, 8 white marbles, and 6 blue marbles. You draw 4 marbles out at random, without replacement. What is the probability that all the marbles are red? 1 The probability that all the marbles are red is...?

3. ### math

A bag contains 5 red marbles, 6 white marbles, and 8 blue marbles. You draw 5 marbles out at random, without replacement. What is the probability that all the marbles are red? The probability that all the marbles are red is? What

4. ### Probability!

A bag contains 5 green marbles , 8 red marbles, 11 orange marbles, 7 brown marbles, and 12 blue marbles. You choose a marbles, replace it, and choose again. what is p(red then blue) 20/43 40/43 20/1849 96/1849

1. ### math (check answer plz)

7. A bag containing 4 green marbles, 6 red marbles, 14 orange marbles, 5 brown marbles, and 8 blue marbles. You choose a marble, replace it, and choose again. What is P(red, then blue)? A. 48/1369 B. 14/1369 C. 27/37 D. 14/37***?

2. ### statistics

A bag contains 7 red marbles, 6 white marbles, and 10 blue marbles. You draw 4 marbles out at random, without replacement. What is the probability that all the marbles are red? What is the probability that exactly two of the

3. ### Math 102

A bag contains six marbles, of which four are red and two are blue. Suppose two marbles are chosen at random and X represents the number of red marbles in the sample. Looking for the expected value of X.

4. ### Maths

A bag contains marbles of three different colours red, blue , yellow. 2/5 of the marbles are red. The ratio of the number of blue marbles to the number of yellow marbles is 5:7. What fraction of the marbles in the bag is blue?

1. ### Probability

jeff has 8 red marbles, 6 blue marbles, and 4 green marbles that are the same size and shape. he puts the marbles into a bag, mixes the marbles, and randomly picks one marble. what is the probability that the marble will be blue?

2. ### statistics

a bag contains 4 blue marbles,6 red marbles, 10 yellow marbles and 6 green marbles.What is the probability of not drawing a red marble?

3. ### Math

Jim has a total of 77 red and blue marbles. The number of blue marbles is 5 more than twice the number of red marbles. How many red marbles are there?

4. ### Probability?

A bag contains 7 green marbles, 9 red marbles, 10 orange marbles, 5 brown marbles, and 10 blue marbles. You choose a marble, replace it, and choose again. Find P(red, then blue).