Why might learning by doing decrease the long-run average cost of production? a. as output increases, the production process begins to exhibit decreasing returns to scale. b. as output increases, firms begin to experience economies of scale. c. as cumulative output increases, engineers gain experiences that decrease costs with increasing defects. d. as cumulative output increases, workers become more adept, and the speed at which they produce increases. e. as cumulative output increases, managers become unable to schedule the production process as efficiently.

Lavage rapide is a canadian company that owns and operates a large automatic car wash facility near montreal. the following table provides data concerning the company’s costs: fixed cost per month cost per car washed cleaning supplies $ 0.70 electricity $ 1,400 $ 0.07 maintenance $ 0.15 wages and salaries $ 4,900 $ 0.30 depreciation $ 8,300 rent $ 1,900 administrative expenses $ 1,400 $ 0.03 for example, electricity costs are $1,400 per month plus $0.07 per car washed. the company expects to wash 8,000 cars in august and to collect an average of $6.50 per car washed. the actual operating results for august appear below. lavage rapide income statement for the month ended august 31 actual cars washed 8,100 revenue $ 54,100 expenses: cleaning supplies 6,100 electricity 1,930 maintenance 1,440 wages and salaries 7,660 depreciation 8,300 rent 2,100 administrative expenses 1,540 total expense 29,070 net operating income $ 25,030 required: calculate the company's revenue and spending variances for august.