Lets assume a firm is considering investing in two projects that has the following cash flows: Interest rate for two projects is 10%.

Could you calculate the Payback period?

Date	Project A	Project B
14-Dec-21	-1000	-1000
14-Dec-22	100	700
14-Dec-23	200	600
14-Dec-24	300	500
14-Dec-25	400	400
14-Dec-26	500	300
14-Dec-27	600	200
14-Dec-28	700	100

Could you draw a graph, that will show how NPV is dependant from interest rate?

Please all formulas using excel.