Help!!! How do you compute for the revised annual depreciation for the year 2008 and future years?

Question

In 2004, the company purchased equipment for $400K estimated to have a 10 yrs useful life, a $49K residual value and annual depreciation of $36K. In 2008, four yrs after, in a technical revaluation, the remaining useful life was 7 yrs and the residual value of $46K

Answer 1

4 yrs after the purchase, the accumulated depreciation = $36,000 x 4 = $144,000, so nbv = $256,000. New depn from 2008 onwards = ($256,000 - $46,000)/7 = $30,000 each yr