Answer:
1. p*=15 ; q*=25
2. Only 20 units are supplied at p=10
3. The ration coupon will cost 10
Explanation:
Considering the following formulas given by the exercise:
D=40-p
S= 10+p
1) Equilibrium price from graph = 15
Equilibrium quantity from graph = 25
2) From the graph only 20 units are demanded at 20 while at p=20 supply is 30. Only 20 units are supplied at p=10
3) The ration coupon will cost 20-10 = 10