on an order of 9 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 10 dozens free . equivalent discount = 1 / 10 * 100 = 10 % . answer a ) 10 %"
subtract(const_100, multiply(divide(9, const_4), const_100))