Answer:
Explanation:
at the beginning
number of adults x
number of children y
we have z nb of children and parents leaving
so we can write
y - z = 4 ( x - z)
and y = 2x
so 2x - z = 4x - 4z
3z = 2x
so z = 2x/3 = 2 x 123 /3 = 82
so at the end we have
123 -82 = 41 number of adults
246 -82 = 164 number of children