Peter processed two catering orders at the sandwich shop where he works. The first order was for 7 trays of club sandwiches and
10 trays of vegetarian sandwiches. That order cost $149. The second order, which cost $10, was for 1 tray of vegetarian sandwiches. This situation is modeled by the matrix equation shown.
Determine the cost of a tray of club sandwiches and the cost of a tray of vegetarian sandwiches.
So if one tray of vegetarian sandwiches cost $10, that means that 10 trays of vegetarian sandwiches would cost $100 (10x10)
Going back to the first order, if we know that 10 trays of vegetarian sandwiches costs $100, then we can subtract that from our overall of $149, leaving us with the cost of 7 trays of club sandwiches
$149 - $100 = $49
therefore, $49 is the cost of 7 trays of club sandwiches
to find the cost of 1 tray, we need to divide $49, by 7
$49 / 7 = $7
therefore, one tray of club sandwiches costs $7 and one tray of vegetarian sandwiches costs $10
