9. If the firm whose costs curves are graphed to the right produces 50 units of output its Total Variable Cost will be:

   Recall that Total Variable Cost is just AVC (Average Variable Cost) times Q (output). When this firm is producing 50 units of output AVC (the height of the AVC curve at 50) is 18. So, Total Variable Cost is equal to the shaded area to the right or 50 x 18 = 900.