Let's break down the costs for both you and your friend.
-
Your purchase (debit card):
- You pay $150 upfront with your debit card.
- Therefore, your total cost is $150.
-
Your friend's purchase (credit card):
- Your friend buys the headphones on a credit card for $150.
- The monthly interest rate is 2%, which means the annual interest rate is \(2% \times 12 = 24%\).
To calculate your friend's total payment at the end of the year, we can use the formula for simple interest:
\[ \text{Total payment} = \text{Principal} \times (1 + \text{interest rate}) \]
Where:
- Principal = $150
- Interest rate for one year = 24% = 0.24
Now, calculating:
\[ \text{Total payment} = 150 \times (1 + 0.24) = 150 \times 1.24 = 186 \]
So your friend will end up paying $186 after one year.
- Comparing costs:
- Your total cost = $150
- Your friend's total cost = $186
Now we can find out who spends less and by how much:
\[ 186 - 150 = 36 \]
Therefore, your friend spends $36 more than you.
Conclusion: You spend $36 less than your friend.