Answer:
20 children.
Explanation:
We can solve this using an equation or simple mental math:
The equation: x=children x+20=adults
x + (x+20) = 60
2x + 20 = 60
2x = 40
x = 20
Mental Math: 40 plus 20 is 60 and 40 is 20 more than 20 so there are 40 adults and 20 children.