when the price of an article was reduced by 15 % its sale increased by 80 % . what was the net effect on the sale ?
if n items are sold for $ p each , revenue is $ np . if we reduce the price by 15 % , the new price is 0.85 p . if we increase the number sold by 80 % , the new number sold is 1.8 n . so the new revenue is ( 0.85 p ) ( 1.8 n ) = 1.53 np , which is 1.53 times the old revenue , so is 53 % greater . answer : c
subtract(divide(multiply(add(80, const_100), subtract(const_100, 15)), const_100), const_100)