To determine the percentage discount Amy receives from the "buy 3 get 1 free" promotion, let's break down the calculation:

1. Normal Cost:

   • If Amy were to buy 4 cans without any promotion, she would pay for all 4 cans.

2. Promotion Applied:

   • With the promotion, Amy buys 3 cans and gets the 4th can for free. Therefore, she only pays for 3 cans instead of 4.

3. Discount Calculation:

   • The discount is the cost of 1 can since she gets 1 can free out of the 4.

4. Percentage Discount: $\text{Percentage Discount} = \left(\frac{\text{Cost of 1 can}}{\text{Cost of 4 cans}}\right) \times 100\%$ Since the cost of 1 can is $\frac{1}{4}$ of the total cost of 4 cans: $\text{Percentage Discount} = \left(\frac{1}{4}\right) \times 100\% = 25\%$

Therefore, Amy receives a 25% discount on her purchase.

Would you like any details on the calculation or have any further questions?

Here are 5 related questions to explore:

1. What would be the percentage discount if the promotion was "buy 2 get 1 free"?
2. How much would Amy save if she bought 8 cans of cola under the same promotion?
3. What is the effective price per can of cola after applying the "buy 3 get 1 free" promotion?
4. How would the discount change if the price of each can increased by 10%?
5. What would be the discount if Amy bought 6 cans and applied the "buy 3 get 1 free" promotion twice?

Tip: When analyzing discounts, always consider the total quantity you are paying for versus what you are receiving to calculate the effective discount percentage.