Answer:
The margin of safety in units per month is 11 units per month.
Step-by-step explanation:
Margin of safety in break even analysis refers to the number of units or amount in excess of the break even number of units or amount. The margin of safety in units is calculated as follows,
Margin of safety = Budgeted/Actual sales in units - Break even in units
We first need to calculate the break even in units. The formula for break even in units is,
Break even in units = Fixed cost / Contribution margin per unit
Break even in units = 8700 / (800 - 500)
Break even in units = 29 units per month
Margin of safety in units = 40 - 29 = 11 units per month