Aptitude - Average - Discussion

First 1-19 numbers = each number is -1.
Therefore Adding these numbers the answer is = -19.
Then the 20th number is +19.
Therefore -19+19 = 0
The average of 20 numbers is 0/20=0

In question, if they are consecutive. Definitely the answer will be 10, but they didn't mention what type of numbers are there, it's asking the possibility of max. Positive numbers satisfy the given condition, so in 20 numbers average is 0. So 20 positive numbers can't take place there is a possibility of 19 numbers positive and the remaining number is numerically equal to the sum of those 19 positive numbers but the sign is negative.

We can't take the same 10 positive and 10 negative numbers, as they were asking about AT MAX how many numbers can be positive so the average is 0?

The answer is 19.

At max,

1 + 2 + 3....….... + 19 + (-190) = 0(sum)
So, the average is 0/20= 0.

Therefore at most 19 numbers can be greater than zero & 1 number will be less than it.

@All.

It's like;
2+2+2+2+(-8) = 0 (sum) ;
3+3+(-6) = 0 (sum) ;
1 + 2 + 3....….... + 19 + (-190) = 0(sum) ;
So, the average is 0/20= 0.

So, it is quite possible that 19 of these numbers may be positive and if their sum is a then the 20th number is (-a).