The correct answer is C (13). The gain or loss on the sale of long-lived assets is computed as the sales proceeds minus the carrying amount of the asset at the time of sale. The carrying amount is typically the net book value, calculated as historical cost minus accumulated depreciation. For this equipment, the carrying amount is 50 (historical cost) - 5 (accumulated depreciation) = 45. Therefore, the gain on the sale is 58 (selling price) - 45 (carrying amount) = 13.

Why not A or B?

• A (3) is incorrect because it incorrectly calculates the carrying amount as historical cost plus accumulated depreciation (50 + 5 = 55), leading to an incorrect gain of 58 - 55 = 3.
• B (8) is incorrect because it calculates the gain as selling price minus historical cost (58 - 50 = 8), ignoring the accumulated depreciation.