Chapter 21, Problem 21.6P

I am looking for the correct answer to this financial accounting question with appropriate explanations.

hy teachher please help me

On January 1, 20X2, Maxwell, which uses the straight-line method, purchases a machine for $81,000 that it expects to last for 10 years; Maxwell expects the machine to have a residual value of $12,000. What is the machine's book value at the end of 20X4? i. $54,000 ii. $47,250 iii. $60,300 iv. $57,600