how do i calculate cumlative CF and discounted CF at 10%?

Your company is cons dering two investment projects, each of which requires an up-front expenditure of $50 in. You mate that cost of capital is 10% and that investments will produce the following after-tax cash flows (in millions of dollars): a. What is the regular payback period for each of the projects? b. What is the discounted payback period for each of the projects? c. If the two projects are independent and the cost of capital is 10%, which projects should the firm undertake? Why? d. If the two projects are mutually exclusive and the cost of capital is 5%, which projects should the firm undertake? Why? e. If the two projects are mutually exclusive and the cost of capital is 15%, which projects should the firm undertake? Why? f. What is crossover rate? g. If the cost of capital is 10%, which is the MIRR of each project