Enviro Tech plans to replace an old piece of research equipment which is obsolet+ and becoming more unreliable under the stress of daily operations. The equipmer is fully depreciated, and no salvage value can be realised upon its disposal. One piece of replacement equipment under consideration would provide annue cash savings of $21 000 before income taxes. The equipment would cost $54 DUI and have an estimated useful life of five years. The equipment is expected to havn no salvage value at the end of five years. Enviro Tech uses the straight line depreciation method on all equiment for both boo and tax purposes. The company is subject to a 40 per cent tax rate. The companj has an after tax required rate of return of 14 per cent