Answer:
a. Degree of Operating Leverage = Contribution Margin / Net Income
Armstrong Company = 260,000 / 100,000 = 2.6
Contador Company = 447,000 / 100,000 = 4.47
b. Armstrong Contador
Sales revenue 544,500 544,500
Variable costs 258,500 52,800
Contribution margin 286,000 491,700
Fixed Costs 160,000 347,000
Net Income $126,000 $144,700
Calculation of Sales revenue increase by 10%
495,000 * 1.10 = 544,500
235,000 * 1.10 = 258,500
48,000 * 1.10 = 52,800