need answer plzzzzz

Q3: Assume that you are investing a certain sum of money (assume any amount without using 0 to form the number eg. 11111) at simple interest for a period of 10 years, so that after 10 years you get 2.8 times return of the number you assumed (eg 2.8x 11111). What will be the rate of interest applicable if it is compounded annually, if you invest the same amount for the same period with the same return. If you invest Rs.2000 annually at the same rate of compound interest what will be the return after a period of 8 years