on an order of 19 dozen boxes of a consumer product , a retailer receives an extra dozen free . this is equivalent to allowing him a discount of :
"clearly , the retailer gets 1 dozen out of 20 dozens free . equivalent discount = 1 / 20 * 100 = 5 % . answer d ) 5 %"
subtract(const_100, multiply(divide(19, const_4), const_100))