Can please someone solve to me this question with clear explaination. Thanks in advance.

Consider the following two mutually exclusive investment alternatives with given (MARR- 10%) Year 0 Project A'1 15,000$ 7,500 $ 7,500 $ 7,500 $ 23.5 % Project A2 20,000 $ 8,000 $ 15,000 $ 5,000 $ 20 % a) Find the best alternative of A1 and A2 based on the present worth incremental investment. b) Find the best alternative of Al and A2 based on the IRR incremental investment