by selling 16 pencils for a rupee a man loses 5 % . how many for a rupee should he sell in order to gain 15 % ?
"85 % - - - 16 105 % - - - ? 85 / 105 * 16 = 8 answer : a"
multiply(divide(const_1, multiply(add(const_100, 15), divide(const_1, subtract(const_100, 5)))), 16)