The short run variable costs below are for a firm in a perfectly competitive market. All firms producing this good have the same costs. The demand is the market demand for the good this firm produces
FIRM MARKET DEMAND
Q VC P Q P Q
1 12 10 500 19 320
2 21 11 480 20 300
3 31 12 460 21 280
4 43 13 440 22 260
5 58 14 420 23 240
6 78 15 400 24 220
7 105 16 380 25 200
8 140 17 360 26 180
18 340 27 160
Find the quantity this firm will produce in the short run if the price of output is $20. If $20 is the short run competitive equilibrium price, find the number of firms in the market.