Please provide a formular for me to follow example PVF .... I also need a graph or a time line profile

13. NPV versus IRR. Here are the cash flows for two mutually exclusive projects: (LO8-1 and LO8-2) Project

C0 C1 C2 C3

A -$20,000 +$8,000 +$8,000 +$ 8,000

B - 20,000 0 0 + 25,000

a. At what interest rates would you prefer project A to B? ( Hint: Try drawing the NPV profile of each project.) .

b.What is the IRR of each project?