A company paid $50,000 for some research equipment, which it believes will have zero salvage value at the end of its 5-year life. What is the book value of the equipment after 3 years? Next, supposing that the equipment is sold for $30,000 at the end of the third year, how much gain or depreciation capture is there? Answer both questions using

(a) Straight line

(b) Double declining balance

(c) Sum-of-years-digits

(d) 100% bonus depreciation

(e) Modified accelerated cost system (MACRS); research equipment belongs to the 5-year MACRS class