7. Challenge question. Construct NPV profiles for both projects using discount rates of 1% through 15% at intervals of one percentage point. At ap- proximately what discount rate does the nano test tube project become superior to the microsurgery kit project? You are better off solving this problem using an electronic spreadsheet. Cash Flow Nano Test Tubes Microsurgery Kits Investment -$11,000 -$11,000 Cash flow year 1 Cash flow year 2 $ 2,000 $ 4,000 $ 3,000 Cash flow year 3 $ 4,000 $ 4,000 Cash flow year 4 $ 4,000 $ 5,000 Cash flow year 5 $ 7,000 $ 4,000 $ 4,000