by selling an article at rs . 500 , a profit of 25 % is made . find its cost price ?
"sp = 500 cp = ( sp ) * [ 100 / ( 100 + p ) ] = 500 * [ 100 / ( 100 + 25 ) ] = 500 * [ 100 / 125 ] = rs . 400 answer : a"
divide(multiply(500, const_100), add(const_100, 25))