some of 60 % - intensity red paint is replaced with 30 % solution of red paint such that the new paint intensity is 40 % . what fraction of the original paint was replaced ?
"let total paint = 1 let amount replaced = x 60 ( 1 - x ) + 30 x = 40 x = 2 / 3 answer : a"
divide(subtract(divide(40, const_100), divide(60, const_100)), subtract(divide(30, const_100), divide(60, const_100)))