Starling Co. is considering disposing of a machine with a book value of $23,700 and estimated remaining life of five years. The old machine can be sold for $6,000. A new high-speed machine can be purchased at a cost of $65,900. It will have a useful life of five years and no residual value. It is estimated that the annual variable manufacturing costs will be reduced from $23,200 to $20,700 if the new machine is purchased. The differential effect on income for the new machine for the entire five years is a(n)