A cost that changes with the level of activity is a: O total cost. fixed cost. O variable cost. O mixed cost. If Jewel Ltd's selling price is $8 per unit, variable costs are $3 per unit and fixed costs are $300 000, the break-even number of sales units is: O 37 500 units. 25 000 units. O 60 000 units. O 100 000 units