Answer: Contribution margin is 1,650
Explanation:
Contribution margin is calculated with the Net sales minus de Variable cost.
Considering that the sales price per sandwich is 5.25 and the quantity sold was 600 sandwiches the Net sale amount is 3,150.
To calculate the variable cost you use the variable cost per sandwich and the quantity sold, the total variable cost is 1,500.
The contribution margin resulted in 1,650 (3,150 minus 1,500), with this amount the fixed cost per month could be covered.