The following questions

See also application questions. The answer is 5.

Suppose that after the price reduction, the number of fans attending the first game is W, the ticket price is Y, the income of the first game is 30W, the number of fans attending the second game is (1+1/2) w = 3/2w =1.5w, and the income of the second game is1.5w * y. ..

Ticket revenue is higher than the entrance 1/4, so 1.5WY/30W=5/4.

So Y=25

Finally, 30-25=5.