Final answer:
The function that represents the interest on this loan after years is Interest = Principal × Rate × Time.
Step-by-step explanation:
The function that represents the interest on this loan after years can be calculated using the formula for simple interest:
Interest = Principal × Rate × Time
In this case, the principal is $8,000, the rate is unknown, and the time is 2 years. The interest paid back is $8,160, so we can rewrite the formula as:
$8,160 = $8,000 × Rate × 2
Dividing both sides of the equation by $8,000 × 2 gives:
Rate = $8,160 / ($8,000 × 2)
Solving this equation gives a rate of 0.51, or 51%.