Need help using Excel:

Required rate of return is 10%. Net Cash Flow Year Project A Project B 0 -$2,000 -$2,500 1 $900 $1,500 2 $1,100 $1,300 3 $1,300 $800 a) Calculate the payback period for each project. b) Calculate the net present value for each project. c) Which project do you think will be approved, if only one project can be approved? Why? d) What if the required rate of return was 20%?