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Example 3.22 from Elementary Algebra, 3.2 Solve Percent Applications
Eduardo noticed that his new car loan papers stated that with a 7.5% interest rate, he would pay $6,596.25 in interest over 5 years. How much did he borrow to pay for his car?
Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.
| Step 1. Read the problem. | |
| Step 2. Identify what we are looking for. | the amount borrowed (the principal) |
| Step 3. Name what we are looking for. Choose a variable to represent that quantity. |
Let principal borrowed. |
| Step 4. Translate into an equation.
Write the formula. Substitute in the given information. |
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| Step 5. Solve the equation.
Divide. |
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| Step 6. Check: Does this make sense?
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| Step 7. Answer the question with a complete sentence. | The principal was $17,590. |
The book's Try It right after this example: same idea, new numbers. Only the answer is given.
Sean’s new car loan statement said he would pay $4,866.25 in interest from an interest rate of 8.5% over 5 years. How much did he borrow to buy his new car?
How did it go?