Question 311293
Let the number of children = x
And the number of adults   = y
Total number      x+y = 2,200   ...(1)
Total collection  1.5x+4y=5050  ...(2)
(1)*4=>           4x+4y = 8,800 ...(3)
(3)-(2)=>         2.5 x = 3,750
                      x = 3750/2.5
                      x = 1500
(1)=>   1500+y=2200
y=2200-1500
y=700
So, the number of children = 1500
And the number of adults   = 700