The figure below is a contour diagram of the monthly payment on a

$5$

$-$

year car loan as a function of the interest rate and the amount borrowed for a used car.

loan amount

$($

$

$)$

What is the interest rate if the monthly payment is $

$1$

$6$

$0$

$$when you borrow $

$7$

$0$

$0$

$0$

$,$

Give your answer to the nearest percent.

$\%$

$($

b

$)$

$$Suppose you borrow $

$5$

$0$

$0$

$0$

$$at an interest rate of

$7$

$\%$

$.$

$$How much more money could you borrow if the interest ra$

$8$

$0$

$0$

te was only

$4$

$\%$

$$instead$?$ poandssible answer choices are $

$1$

$0$

$0$

$,$

$$$

$8$

$0$

$0$

$,$

$$$

$5$

$5$

$0$

$0$

$,$

$$$

$5$

$0$

$0$

$,$

$$and $

$1$

$0$

$0$

$0$