by selling an article at rs . 600 , a profit of 30 % is made . find its cost price ?
"sp = 600 cp = ( sp ) * [ 100 / ( 100 + p ) ] = 600 * [ 100 / ( 100 + 50 ) ] = 600 * [ 100 / 150 ] = rs . 400 answer : a"
divide(multiply(600, const_100), add(const_100, 30))