Answer:
9 Prizes
Explanation:
She begins with 420 tickets.
She goes on 2 rides for 75 tickets each so 420-75-75= 270
She then attends the concert for 180 tickets so 270-180= 90
Now she is left with 90 tickets. 10 tickets = 1 prize therefore you can do 90/10 = 9
9 PRIZES