the ratio of the cost price and selling price is 4 : 5 . the profit percent is ?
"let the c . p . = $ 4 x then s . p . = $ 5 x then , gain = 5 x - 4 x = $ x gain % = x / 4 x * 100 = 25 % answer is b"
multiply(subtract(divide(5, 4), const_1), const_100)