1) Castel and Rob are selling cheesecakes for a school fundraiser. Customers can buy New York style
cheesecakes and apple cheesecakes. Castel sold 5 New York style cheesecakes and 6 apple cheesecakes
for a total of $85. Rob sold 6 New York style cheesecakes and 6 apple cheesecakes for a total of $90.
What is the cost each of one New York style cheesecake and one apple cheesecake?