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.