Each of 36 students at a school play bought either a cup of orange juice or a sandwich. A cup of orange juice costs $1 and a sandwich costs $3. The total amount collected was $76. How many students bought orange juice, and how many bought a sandwich? Let x represent the number of students who bought a cup of orange juice and y represent the number of students who bought a sandwich. Then the problem can be represented by this system of equations:
x + 3y = 76
x + y = 36
Answer the questions to solve the problem.
1. Explain what you should do with the two equations to eliminate one of the variables. (2 points)

2. Find the value of y. (3 points)

3. Find the value of x. (2 points)

4. Interpret the solution and check the values in the system. (3 points)