please show me the calculus process Thanks Jennings Creation

please show me the calculus process,

Thanks.

Jennings Creations is considering an investment in a computer that is capable of producing various images that are useful in the production of commercial art. The computer would cost $20,000 and have an expected life of eight years. The computer is expected to generate additional annual net cash receipts (before-tax) of $6,000 per year. The computer will be depreciated according to the straight-line method and the firm\'s marginal tax rate is 25 percent. Refer to Jennings Creations. What is the after-tax net present value of the proposed project (using a 16 percent discount rate) Present value tables or a financial calculator are required, $(4,797) $2,261 $6,062 $(454)

Solution

Depreciation = 20000 / 8 = $ 2500 per year

Tax savings on depreciation = 2500 * .25 =$ 625

After tax cash receipts = 6000 (1 -.25)

                                         = 6000*.75

                                         = 4500

Total after tax benefit = 4500+ 625 =$ 5125

Present value of benefit =PVAF@16%,8 * Annual benefit

                                           = 4.34359*5125

                                           = 22260.90

NPV = Present value -Initial investment

          = 22260.9 - 20000

          = 2260.9     (approx 2261 )

correct option is \"B\"