Idon't get this > -< i also need to know how you got it so i can learn the next time

Mr. and mrs. wallace have decided to buy a car for $21,600. they finance $15,000 of it with a 5-year auto loan at 2.9% arp. what will be their monthly payment be? a. $268.20 b. $268.86 c. $269.54 d. $387.16 (monthly car loan payment per $1,000 borrowed) i need !

Nikolas calculated the volume of the prism. his work is shown below.

Ineed some on this. not sure how to solve.