The number of red marbles varied inversely as the square of the number of blue marbles. When there were 4 reds, there were 20 blues. How many reds would there be if there were only 4 blues?
r = k/b^2 where k is a constant.
Find k from: 4 = k/20^2 so k = 4*20^2 = 1600
When there are 4 blues: r = 1600/4^2 or r = 1600/16, so r = 100
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okay thank you :)