help please

Carmel Corporation is considering the purchase of a machine costing $45,000 with a 4 year useful life and no salvage value. Carmel assumes that the annual net cash flows from the machine will be received uniformly throughout each yeor in caiculating the accounting rate of return, what is Carmel's average investment? Multople Chace 545,000 511.250. 528325 572500 54003