Afirm's minimum average variable cost of $25 a backpack occurs when the firm produces 4 backpacks a day. draw the firm's supply curve. label the supply curve below $25 a backpack s_0. label the supply curve above $25 a backpack s_1. a firm's supply curve is the same as the average total cost curve at all points above the shutdown point includes the marginal cost curve at all pewits above minimum average variable cost is vertical at the shutdown point is the same as the average variable cost curve at al points above the shutdown point