The regular price of a swimsuit in the junior department of a store is $54. The store advertises an end-of-season sale at 40% off the regular price of all swimsuits. Two weeks later the store advertises a bonus sale at an additional 1/5 off the end-of-season sale price of all swimsuits. Shannon and Mary decide this is a great time to shop for swimsuits. Shannon figures that the swimsuits are now 60% off the regular price. Mary disagrees because she figures that the total discount is actually less than 60%.
a. What is the cost of a swimsuit during the end-of-season sale? Justify your reasoning using a model.
b. What is the cost of a swimsuit during the additional 1/5-off bonus sale? How can you show this with a model?
c. Did Shannon or Mary figure the discount correctly? Use a model to explain.