Final answer:
To find the cost of one sandwich, set up a system of equations using the given information and solve for the cost of one sandwich.
Step-by-step explanation:
To find the cost of one sandwich, we need to set up a system of equations using the given information. Let's assume the cost of one sandwich is x dollars.
From the first purchase, we know that 3 sandwiches and 2 drinks cost $15.75. So, we can write the equation: 3x + 2y = 15.75, where y represents the cost of one drink.
From the second purchase, we know that 2 sandwiches and 1 drink cost $9.85. So, we can write the equation: 2x + y = 9.85.
We can now solve this system of equations to find the value of x, which represents the cost of one sandwich.