You can't really determine the amount of computers from this question, they're obviously not going to have one computer for everyone so half third, or even a fourth of the school population
RS is 68 and T is 92 if you want an explanation then i gotten but u said quick so maybe it is timed idk
Expand the brackets first
5(wx-v) = 9(x + v)
5wx - 5v = 9x + 9v
Get all x's on one side and everything on on the other side
9x - 5wx = 9v + 5v
factorise out the x
x(9-5w) = 14v
then divide by 9-5w
x = 14v/(9-5w)
Ok soo
-5x+x/2=9
- 4x/2=9
-(2^2-1 *x)=9
2x/2=- 9/2
x=- 9/2
x= -4 1/2