by selling 15 pencils for a rupee a man loses 15 % . how many for a rupee should he sell in order to gain 15 % ?
"85 % - - - 15 115 % - - - ? 15 / 115 * 15 = 11 answer : c"
multiply(divide(const_1, multiply(add(const_100, 15), divide(const_1, subtract(const_100, 15)))), 15)