Question 26423
Let original number of students be "x"
Their individual cost is 360/x
If six more join there are now "x+6"
Individual cost for this expanded group would be 360/(x+6)
But this last individual cost is $2 less than the original individual cost.
EQUATION:
 Original indiv. cost - New indiv cost = $2
360/x - 360/(x+6)= 2
1/x -1/(x+6)= 1/180
6/[x(x+6)] = 1/180
x^2+6x-1080=0
(x+36)(x-30)=0
x=30 (size of original group)

Cheers,
stan H.