Revenue, total cost, and profit are three exact expressions from the same inputs.
highlighted = computed this step
Revenue line
Revenue is unit price $10 times quantity. Motivation: start with the money coming in.
R(q)=$10q
Total cost line
Total cost is fixed cost $60 plus variable cost $4 per unit.
C(q)=$60+$4q
Profit formula
Profit is revenue minus total cost, so the contribution margin $6 multiplies quantity before fixed cost is subtracted.
Π(q)=$6q−$60
Formula scope
The formula is a model line, not a demand forecast. Break-even analysis assumes the fixed cost, unit price, and unit variable cost are known and stay constant. It does not estimate demand, capacity, taxes, or whether every unit can be sold.