The diagram shows a contour diagram for the monthly payment P as a function of the interest rate,r%, and the amount, L, of a 5-year loan. Estimate at...

The diagram shows a contour diagram for the monthly payment P as a function of the interest rate,r%, and the amount, L, of a 5-year loan. Estimate at the following points. In each case, give the units and a meaningful interpretation of your answer.

(a) r = 8, and L = 4000

(b) r = 13, and L = 7000

Full version r available in the attachment