Chen and Angelina each opens new investment accounts at time 0. Chen deposits 1000 into his account and Angelina deposits 700 into her account. Both accounts earn effective rate of interest of i compounded annually. Chen and Angelina both earn Y amount of interest on the 10th year and 15th year respectively. (a) Calculate Y. (b) Evaluate their total profit earned after 20 years invested. [7 marks] [2 marks]