1. Tara is going to invest $80 000 in an account. The account pays interest at the rate of 6% per annum, compounding monthly. What should be her monthly contribution to the investment to have an account balance of $120 000 at the end of 18 months? Give your answer correct to the nearest dollar.

2. If Tara invests $80 000 in an account which pays interest at the rate of 6.5% per annum, compounding fortnightly, and at the end of each fortnight she adds $1 700 to the investment, how much will the account balance be at the end of 24 months? Give your answer correct to the nearest dollar.