The graph shows the demand cave for ice cream cones and the

The graph shows the demand cave for ice cream cones and the market price of the ice cream cone.

Solution

Consumer surplus is measured by the area between demand curve and price.

Price is fixed at $2.

At current demand of 40 units, consumer surplus = (1/2) x $(4 - 2) x 40 = (1/2) x $2 x 40 = $40

If demand doubles to 80 units, new consumer surplus = (1/2) x $(4 - 2) x 80 = (1/2) x $2 x 80 = $80

Increase in consumer surplus = $(80 - 40) = $40