Write a system of equations to describe the situation below, solve using any method, and fill in the blanks. This morning, Pam processed two catering orders at the sandwich shop where she works. The first order was for 9 trays of club sandwiches and 4 trays of vegetarian sandwiches, at a cost of $61. The second order, which cost $70, was for 10 trays of club sandwiches and 5 trays of vegetarian sandwiches. How much do the trays cost?
A tray of club sandwiches costs $ , and a tray of vegetarian sandwiches costs $ .