Question

Zoey decides to buy a new smartphone for $800 with her credit card. The yearly interest rate on her credit card is 30%. How much interest will Zoey need to pay it off? How much will her $800 smartphone end up costing her?
Zoey will need to pay $___ in interest on her smartphone purchase if she takes a year to pay it off. Her $800 smartphone will end up costing her $__

Answer 1

To calculate the interest Zoey will need to pay on her $800 smartphone purchase with a yearly interest rate of 30%, we can use the formula for simple interest:

\[
\text{Interest} = \text{Principal} \times \text{Rate} \times \text{Time}
\]

Where:
- Principal = $800 (the cost of the smartphone)
- Rate = 30% = 0.30 (in decimal form)
- Time = 1 year

Plugging in the values:

\[
\text{Interest} = 800 \times 0.30 \times 1 = 240
\]

So, Zoey will need to pay **$240** in interest on her smartphone purchase if she takes a year to pay it off.

To find out how much her $800 smartphone will end up costing her, we add the interest to the principal:

\[
\text{Total Cost} = \text{Principal} + \text{Interest} = 800 + 240 = 1040
\]

Thus, her $800 smartphone will end up costing her **$1040**.

In summary:
- Zoey will need to pay **$240** in interest.
- Her $800 smartphone will end up costing her **$1040**.