Starling Co. is considering disposing of a machine with a book value of $12,500 and estimated remaining life of five years. The old machine can be sold for $1,500. A new high-speed machine can be purchased at a cost of $25,000. 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 $26,000 to $23,500 if the new machine is purchased. The five-year differential effect on profit from replacing the machine is a(n) decrease of $11,000 decrease of $15,000 increase of $15,000 increase of $11,000