Answer:
Mr. Johnson borrowed the money at an interest rate of 4.25%.
Explanation:
We can use the formula for simple interest to solve this problem:
Simple Interest = Principal x Rate x Time
Where:
Principal is the amount borrowed.
Rate is the interest rate (as a decimal).
Time is the length of time the money is borrowed for.
We know that Mr. Johnson borrowed $8000 for 4 years and repaid a total of $10,320. We can use this information to set up an equation:
10,320 = 8000 + 8000 x Rate x 4
Simplifying this equation:
10,320 = 8000 + 32000 x Rate
Dividing both sides by 32000:
Rate = (10,320 - 8000) / (8000 x 4) = 0.0425 or 4.25%
Therefore, Mr. Johnson borrowed the money at an interest rate of 4.25%.
Hope this helped! Sorry if it didn't. If you need more help, ask me! :]