A sports-goods shop has tennis balls of 3 colors - red, green and white. The number of white balls is 60% more than number of red balls and the number of green balls is 12.5% less than number of white balls. If total number of balls is 120, then how many green balls are there ?

42

Let the number of red balls be 5

Then, white balls = \(\frac{8}{5}\) x 5 = 8 

                                 (because 60% more = \(\frac{160}{100}\) = \(\frac{8}{5}\) )

green balls = \(\frac{7}{8}\) x 8 = 7

                           (because 12.5% less = \(\frac{87.5}{100}\) = \(\frac{7}{8}\) )

                  Red  :  White  :  Green

Ratio =         5    :       8   :       7  ⇒ total = 20R

Given, 20R = 120

              R = 6

No. of green balls = 7R = 42