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