solve question 19 ONLY please

28. American General offers a 7-year ordinary annuity with a guaranteed rate of 6.35% compounded annually. How much should you pay for one of these annuities if you want to receive payments of $10,000 annually over the 7-year period? In Problems 15-22, use the future value formula (6) to find each of the indicated values. 15. n=20;i=0.03;PMT=$500;FV= ? 16. n=25;i=0.04;PMT=$100;FV= ? 17. FV=$5.000;n=15;i=0.01;PMT= ? 18. FV=$2,500;n=10;i=0.08;PMT= ? 19. FV=$4,000;i=0.02;PMT=200;n=? 31. If you buy a computer directly from the manufacturer for $2,500 and agree to repay it in 48 equal installments at 1.25% interest per month on the unpaid balance, how much are your monthly payments? How much total interest will be paid