What are the average fixed cost, average variable cost and average cost of a firm ? How are they related ?

SOLUTION :Average fixed cost (AFC) REFERS to the per unit fixed cost of PRODUCTION. Average variabe cost (AVC) refers to the per unit variable cost of production. Average cost (AC)refers to the per unit total cost of production. AC is the sum total of AFC and AVC.
"ImportantObservation: AC, AVC and AFC"
1.AC curve will always lie above the AVC curvebecause AC,at all levels of output includes both AVC and AFC.
2.AVC reaches its minimum point at a level of output lower than that of AC because when AVC is at its minimum point, AC is still falling because of falling AFC.
3.As the output increases,the gap between AC and AVC curves decreases,but, they NEVER intersect each other .It happens because the vertical distance between them is AFC , which can never be zero.