When the price of an article was reduced by 40% its sale increased by 80%. What was the net effect on the sale?
Option:A)8% increase
B)4% decrease
C)6% increase
D)66% increase
E)66% decrease
A.if n items are sold for $p each, revenue is $np. If we reduce the price by 40%, the new price is 0.6p. If we increase the number sold by 80%, the new number sold is 1.8n. So the new revenue is (0.6p)(1.8n) = 1.08np, which is 1.08 times the old revenue, so is 8% greater.
ANSWER:A