Head-First Company plans to sell 4,200 bicycle helmets at $71 each in the coming year. Unit variable cost is $44 (includes direct materials, direct labor, variable factory overhead, and variable selling expense). Total fixed cost equals $50,000 (includes fixed factory overhead and fixed selling and administrative expense). Required: 1. Calculate the number of helmets Head-First must sell to earn operating income of $67,990. 2. Check your answer by preparing a contribution margin income statement based on the number of units calculated