So, doing the calculations, Marion's had $700,000-240,000=$460,000-160,000 in expenses = $300,000 x 0.4 income tax=120,000 and so 300,000-120,000=$180,000 net value. Preston's had $700,000-40,000 depreciation=$660,000-160,000 expenses =$500,000 x 0.4 taxes= 200,000 taxes so 500,000-200,000=$300,000 net value. The result is Preston's had less depreciation which provided it with more spendable income.