Max and Molly work at a coffee shop. Customers can buy hot chocolate and coffee. On Saturday, Max sold 10 hot chocolates and 12 coffees for a total of $64. On Sunday, Molly sold 10 hot chocolates and 7 coffees for a total of $54.
What is the cost of one hot chocolate and one coffee? Use the variable x to represent the cost of hot chocolate and y to represent cost of coffee.