how many ounces of a 60 % salt solution must be added to 40 ounces of a 20 percent salt solution so that the resulting mixture is 40 % salt ?
"let x = ounces of 60 % salt solution to be added . 2 * 40 + . 6 x = . 4 ( 40 + x ) x = 40 amswer b"
divide(subtract(multiply(divide(40, const_100), 40), multiply(divide(20, const_100), 40)), subtract(divide(40, const_100), divide(20, const_100)))