#### Answer

Plan A offers the better deal and will cost 90 dollars less than Plan B.

#### Work Step by Step

For Plan A, the membership is 100 dollars. The 1500 dollars of merchandise will cost 1200 dollars ( 80% of the 1500 dollars). The 1200 dollars for merchandise plus the 100 dollar membership is a total of 1300 dollars.
For Plan B, the membership is 40 dollars. The 1500 worth of merchandise will cost 1350 dollars (90% of the 1500). The 1350 for merchandise plus the 40 dollars for membership is a total of 1390 dollars.
So, Plan A costs less. The difference between Plan A and Plan B is 1390 - 1300 or 90 dollars.