Equipment was purchased on January 1 for $30,000 with an estimated residual value of $5,000. The current year's Depreciation Expense is $5,000, calculated on the straight-line basis, and the balance of the Accumulated Depreciation account at the end of the year is $10,000. The remaining useful life of the equipment is 3 years. 5 years 6 years 9 years. O None of the above