Penn Medical Center, a for-profit hospital, is considering the purchase of a new 64 slice CT scanner. The cost of the new scanner is $4 million and will be depreciated over 10 years on a straight line basis to $0 savage value. The tax rate is 40%. The financing options include either borrowing the full cost of the scanner or leasing a scanner. The lease option is a five-year lease with equal before-tax lease payments of $975,000 per year. The borrowing alternative is a five-year loan covering the entire cost of the scanner at an interest rate of 5%. The after-tax cost of debt is 3%. Should Penn Medical lease the equipment or borrow the money

No I just want to know how to do this correctly, what formula should I be using

I just need some guidance on what formula to use to calculate this what am I using, to do the calculations