4-A corporation with a 39% combined income tax rate is considering the following investment in research equipment Cash Year Before-Tax Flow 0 -S7,500,000 S650,000 2 $950,000 3 $2,750,000 4 $1,900,000 5 $800,000 6 $450,000 Prepare an after-tax cash flow table assuming MACRS depreciation a. What is the before-tax rate of return? b. What is the after-tax rate of return