Answer:
196 children, 195 adults
Explanation:
Use a for adults and c for children
a + c = 391
6a + 1.25c = 1415
Rearrange the first equation to be one variable alone:
a = 391 - c, then replace a in the second equation with that
6(391 - c) + 1.25c = 1415
2346 - 6c + 1.25c = 1415
2346 - 4.75c = 1415
-4.75c = -931
c = 196
There were 196 children admitted.
Now replace that into the original equation:
a + 196 = 391
a = 195 195 adults attended