4 / 15 of 5 / 7 of a number is greater than 4 / 9 of 2 / 5 of the same number by 8 . what is half of that number ?
let the number be x . then 4 / 15 of 5 / 7 of x - 4 / 9 of 2 / 5 of x = 8  4 / 21 x - 8 / 45 x = 8 ( 4 / 21 - 8 / 45 ) x = 8  ( 60 - 56 ) / 315 x = 8  4 / 315 x = 8 x = ( 8 * 315 ) / 4 = 630  1 / 2 x = 315 hence required number = 315 answer is b .
divide(divide(8, subtract(multiply(divide(4, 15), divide(5, 7)), multiply(divide(2, 5), divide(4, 9)))), 2)