Please answer and show all work to calculate. No excel sheets please

Calculate the NPV and PI for each of the following projects. Which project would you choose if only one could be chosen? If multiple projects could be undertaken, how many would you accept? Assume that the cost of capital is 7% for each project. YEAR iPad 4 iPhone 6 iMac 0 -34,000 -12,500 -15,500 1 27,000 300 9,500 2 14,600 9,500 12,000 3 3,600 4,000 2,400