please explain in details with formula. Thank you

Kingbird Corporation is considering purchasing a new delivery truck. The truck has many advantages over the company's current truck (not the least of which is that it runs). The new truck would cost $55,728. Because of the increased capacity, reduced maintenance costs, and increased fuel economy, the new truck is expected to gencrate cost savings of $8,100. At the end of eight years, the company will sell the truck for an estimated $27,500. Traditionally, the company has used a general rule that it should not accept a proposal unless it has a payback period that is less than 50% of the asset's estimated useful life. Donald Robinson, a new manager, has suggested that the company should not rely only on the payback approach but should also use the net present value method when evaluating new projects. The company's cost of capital is 8%. (a) Calculate the cash payback period and net present value of the proposed investment. Iff the net present value is negative use elther o negative sign preceding the number eg. 45 or parentheses es. (45). Round cash poybock periad to 2 decimal place, es. 12.51. For calculation purposes, use 5 decimal places as dlsplayed in the factor table provided, eg. 1.25124 and net present value to 0 decimal ploces e.3. 5,275 .)