Least AC is when production is 5.368 tons. At this point (5.4 is closest can get by moving slider) AC = MC, and the curves intersect. Note that the MC curve intersects the AC curve at its minimum. For lower production levels, MC is below AC so it is possible to reduce AC by increasing production (the marginal unit of production is cheaper, and reduces average cost). But for higher production levels, MC is above AC, and any further increase in production will raise average costs (as the marginal unit is now more expensive than average).
