Answer
Breakeven Point in Units = Fixed Costs / Weighted Average Contribution Margin per Unit
Breakeven Point in Units = 405,000 / 3.8571
Breakeven Point in Units = 105,000 units
Work Step by Step
Weighted Average Contribution Margin per Unit = (Contribution Margin per Unit A * Percentage of A) +(Contribution Margin per Unit B * Percentage of B) +(Contribution Margin per Unit C * Percentage of C)
Weighted Average Contribution Margin per Unit = (5 * 24,000 / 168,000) + (4 * 96,000 / 168,000) + (3 * 48,000 / 168,000)
Weighted Average Contribution Margin per Unit = 0.7143 + 2.2857 + 0.8571
Weighted Average Contribution Margin per Unit = 3.8571