a shirt goes on sale for 80 % of its original price . one week later , the sale price is marked down 20 % . the final price is what percent of the original price ?
"just assume original price is 100 . sale price = 80 then it is marked down by 20 % = 80 - 16 = 64 . hence it is 64 % od the original price . hence answer is d ."
subtract(80, multiply(divide(80, const_100), 20))