Problem:
Business is a little slow at Lou's Fine Shoes, so Lou decides to have a sale. On Friday, Lou increases all of Thursday's prices by . Over the weekend, Lou advertises the sale: "Ten percent off the listed price. Sale starts Monday." How much does a pair of shoes cost on Monday that cost on Thursday?
Answer Choices:
A.
B.
C.
D.
E.
Solution:
Thursday's price of is increased or , so on Friday the shoes are marked . Then of or is taken off, so the price on Monday is .
Marking a price higher multiplies the original price by , and reducing a price by multiplies the price by . So the price of a pair of shoes that was originally will be .
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions