Single payment: You need a sum of $20K ($20,000) now and promise to pay it back at the end of 10 years to your in-laws with interest (good luck!). How much will you have to pay back at the end of the 10-year period, if the agreed interest rate is 5% p.y? a. Sketch the time line diagram with cash flow arrows. b. Write the expression F = [20K (F/P, i, n)]. c. Show calculations and