9.On what sum will the compound interest at 7% per annum for three yearscompounded annually be * 3,101.40?210. At what rate per cent will a sum of 640 be compounded to 774.40 in twoyears?11. At what rate per cent will a sum of 64,000 be compounded to 68,921 in threeyears?12. In how many years will 8,000 amount to 9,261 at 5% per annum compoundedannually?13. In what time will a sum of 3,750 at 20% per annum compounded annuallyamount to 6,480?prin.Ant.14. The difference between the compound interest and simple interest on a certainpolsum of money at 62 % per annum for three years is + 46. Find the sum.32915. The difference between the compound interest and the simple interest on acertain sum of money at 15% per annum for three years is 283.50. Find the sum.%116. Find the amount and the compound interest on 12,800 for one year at 7per annum compounded semi-annually.​