The average of 20 non-zero numbers is zero. Of them, how many may be greater than zero, at the most?

Question

The average of 20 non-zero numbers is zero. Of them, how many may be greater than zero, at the most?

1. A. 0
2. B. 10
3. C. 18
4. D. 19 (Correct answer)

Correct Answer

Option D — 19

Detailed Solution & Explanation

The correct answer is 19.

Key Points

• If the average of 20 non-zero numbers is zero, the sum of all numbers = 0. For this to happen with non-zero numbers, there must be at least one negative number.
• The maximum number of positive numbers = 19 (with 1 very large negative number to balance all 19 positives, making sum = 0).