if the cost price of 35 chocolates is equal to the selling price of 21 chocolates , the gain percent is :
"explanation : solution : let c . p . of each chocolate be re . 1 . then , c . p . of 21 chocolates = rs . 21 ; s . p . of 21 chocolates = rs . 35 . . ' . gain % = 14 * 100 / 21 = 66.66 % answer : b"
divide(const_100, divide(21, subtract(35, 21)))