some of 40 % - intensity red paint is replaced with 20 % solution of red paint such that the new paint intensity is 20 % . what fraction of the original paint was replaced ?
"let total paint = 1 let amount replaced = x 40 ( 1 - x ) + 20 x = 20 x = 1 / 1 answer : e"
divide(subtract(divide(20, const_100), divide(40, const_100)), subtract(divide(20, const_100), divide(40, const_100)))