Your answer would be $115.20 for your interest in all. His account balance would be $1015.20 at the end of four years.
I got this answer by first multiplying 900 times .032. I got the .032 by saying that 3 percent is .03, and .2 percent is a .002. .032 would be that percentage in a decimal version. I got 28.8 from that, so that would be your simple interest. Multiply that by four for your total interest together, and add 900 to it to get your answer.
