Assignment:
Lets say Costco price club claims that they sell a 6 pack of Coors Beer at the wholesale price plus an additional 5% off. But with Costco, you also have to pay a yearly membership fee of $60 just to have the privilege of shopping there. The wholesale price of Coors at Costco is $3.50 a six pack. The 5% discount is taken at the register when you pay.
My local grocery is currently running a special on Coors Beer 6 packs where the price is discounted by 10% of the regular price. The regular price is $5.00 a six pack.
Question: What is the minimum number of 6 packs of Coors per month would I have to buy at Costco to make the membership worthwhile as compared to just getting the 10% at my neighborhood grocery store?
Provide complete and step by step solution for the question and show calculations and use formulas.