Greetings!
Answer:
$35.96 to 2.d.p. or 36 to 2.s.f.
Explanation:
We can show this by:
611 = 78x
x being the 78 students
To find 1x which is the price of one student, or one lunch, we can simply divide both sides by 78:

Or:
35.95 = 1x
So each lunch cost 35.96 to 2.d.p. or 36 to 2.s.f.
Hope this helps!