Beth's school is selling tickets to a fall musical. On the first day of ticket sales the school sold 4 adult tickets and 5 child tickets for a total of $70. On the second day the school sold 9 adult tickets and 4 child tickets for a total of $85. Find the price each one adult ticket and the price of one child ticket.
4a+5c = 70
9a+4c = 85
solve to get a=5 and c=10