r" An ofce machine is purchased for $8700. Under certain assumptions its salvage value, V, in dollars, is depreciated according to a method called double declining balance, by basically 67% each year, and' Is given by Wt): 8700(0. 67). where t Is the time. in years after purchase a) Find Vl (t). h) Interpret the meaning of V'(t). W 3) WI) = D