Answer:
40 students
Step-by-step explanation:
We need a system of equations to find x or the students in advance:
2x + 4y = 800
x + y = 220
We can use substitution and isolate y in the second equation, which gives us y = 220 - x.
When we plug this into the first equation, we get 2x + 4(220 - x) = 800 and solving for x gives us x = 40.
