MG, a corporation in the 21 percent marginal tax bracket, owns equipment that is fully depreciated. This old equipment is still operating and should continue to do so for four years (years 0, 1, 2, and 3). MG's chief financial officer estimates that repair costs for the old equipment will be $1,300 in year 0, $1,400 in year 1, $1,500 in year 2, and $1,600 in year 3. At the end of year 3, the equipment will have no residual value.

MG could junk the old equipment and buy new equipment for $5,000 cash. The new equipment will have a three-year MACRS recovery period, should not require any repairs during years 0 through 3, and will have no residual value at the end of year 3.

a. Assume MG cannot make a Section 179 election to expense the $5,000 cost of the new equipment. Which option (keep old or buy new) minimizes MG's after-tax cost? In making your calculations, use a 10 percent discount rate.

b. Assume MG can make a Section 179 election to expense the entire $5,000 cost of the new equipment. Under this change in facts, which option (keep old or buy new) minimizes MG's after-tax cost?