Question 1172818
Assume number of adults = a and number of children = c
Therefore,
        a + c = 120  -------- (1)
and 500a + 400c <= 80000 -----(2)
 
When c=0, a <= 80000/500 = 160
When a=0, c <= 80000/400 = 200
 
So, the possible number of adults and children are:
All values of (a, c) satisfying inequation (2) where a <= 160, c <= 200
 
*[illustration Graph]