Answer: Karl must sell 1350 small heaters and 450 large heaters to break even.
We follow these steps to arrive at the answer:
No. Small Large Total
1 Selling Price per unit 80 250
2 Variable Cost per unit 30 120
3 Number of units sold 2100 700 2800
4 Sales mix 3 1
5 Total sales (1*3) 168000 175000
6 Total Variable Cost (2*3) 63000 84000
7 Contribution Margin (5-6) 105000 91000 196000
Next we compute the Weighted Average Contribution Margin as follows:


Now, Break even point (BEP) is computed as


Since the large and small heaters are sold in the 3:1 ratio, we can find the number of large and small heaters to be sold in order to achieve the break even point at 1800 units.



