Answer:
19,20,21
Step-by-step explanation:
The average is 20. The numbers can be written as: 20+a, 20 +b, 20+c, with a, b, c integers (positive and negative, but higher than - 19),with a+b+c =0.
You have to find the combination a, b, c with the smallest positive integer as its higher number.
Obviously, you start with 1, and find - 1,0,+1 as a suitable solution.
Therefore, the numbers are 20-1, 20,20+1
=> 19,20,21
