Suppose you invest $900 in an account paying 7% interest per year. a. What is the balance in the account after 4 years? How much of this balance corresponds to "interest on interest"? b. What is the balance in the account after 29 years? How much of this balance corresponds to "interest on interest"? a. What is the balance in the account after 4 years? The balance in the account (with compounded interest) after 4 years is $ 1179.72. (Round to the nearest cent.) The balance in the account (with simple interest) after 4 years is $ (Round to the nearest cent.)