Answer:
The answer would be 20.
Explanation:
To find out we can start from the beginning.
15 would no be the balance point since it is at the farthest end. So we can cross that off.
19 is close to the middle but not exsactly. So we cross that off aswell.
20 is somewere in the middle so that is good so far.
80 isen't even on the data set. So 80 is crossed off.
Now we are only left with 20, so that is our best choice.
Hope this helped! :)