by selling 16 pencils for a rupee a man loses 28 % . how many for a rupee should he sell in order to gain 28 % ?
"72 % - - - 16 128 % - - - ? 72 / 128 * 16 = 9 answer : b"
multiply(divide(const_1, multiply(add(const_100, 28), divide(const_1, subtract(const_100, 28)))), 16)