加里森管理会计12th,第十二章答案

Exercise 12-11 (20 minutes)

1. Fixed cost per mile ($3,500* ÷ 10,000 miles) . $0.35

Variable operating cost per mile ..................... 0.08

Average cost per mile .................................... $0.43

* Depreciation ............................. $2,000

Insurance (960)

Garage rent (480)

Automobile tax and license (60)

Total ........................................ $3,500

2. The variable operating costs would be relevant in this situation.

The depreciation would not be relevant since it relates to a sunk cost. However, any decrease in the resale value of the car due to its use would be relevant. The automobile tax and license costs would be incurred whether Samantha decides to drive her own car or rent a car for the trip during spring break and are therefore irrelevant. It is unlikely that her insurance costs would increase as a result of the trip, so they are irrelevant as well. The garage rent is relevant only if she could avoid paying part of it if she drives her own car.

3. When figuring the incremental cost of the more expensive car,

the relevant costs would be the purchase price of the new car (net of the resale value of the old car) and the increases in the fixed costs of insurance and automobile tax and license. The

original purchase price of the old car is a sunk cost and is

therefore irrelevant. The variable operating costs would be the same and therefore are irrelevant. (Students are inclined to think that variable costs are always relevant and fixed costs are always irrelevant in decisions. This requirement helps to dispel that

notion.)

Relevant Costs

Item Make Buy Direct materials (60,000 @ $4.00) ............. $240,000

Direct labor (60,000 @ $2.75) ................... 165,000

Variable manufacturing overhead

(60,000 @ $0.50) .................................. 30,000

Fixed manufacturing overhead, traceable

(1/3 of $180,000) .................................. 60,000

Cost of purchasing from outside supplier

(60,000 @ $10) ..................................... $600,000 Total cost ................................................. $495,000 $600,000 The two-thirds of the traceable fixed manufacturing overhead costs that cannot be eliminated, and all of the common fixed manufacturing overhead costs, are irrelevant.

The company would save $105,000 per year by continuing to make the parts itself. In other words, profits would decline by $105,000 per year if the parts were purchased from the outside supplier.