by selling 12 pencils for a rupee a man loses 12 % . how many for a rupee should he sell in order to gain 18 % ?
"88 % - - - 12 112 % - - - ? 88 / 112 * 12 = 9 answer : a"
multiply(divide(const_1, multiply(add(const_100, 18), divide(const_1, subtract(const_100, 12)))), 12)