a. Based on PW method, Design is more economical. b. The modified B/C ratio of Design Y is The modified B/C ration of Design Z is c. The incremental B/C ratio is (Round to two decimal places) (Round to two decimal places) (Round to two decimal places) Therefore, based on the B/C ratio method, Design is more economical d. The discounted payback period of Design Y is The discounted payback period of Design Z is years (Round to one decimal place) years (Round to one decimal place) Therefore, based on the payback period method, Design would be preferred. (e) Why could the recommendations based on the payback period method be different from the other two methods? A. because the payback period gives more weight to the cash flows after the payback period B. because the payback period method ignores the cash flows after the payback period