Question: The average of three numbers is 30. If one number is removed, the average becomes 25. What is the removed number?
Options:
Correct Answer: 35
Solution:
Let the three numbers be x, y, z. (x + y + z) / 3 = 30 => x + y + z = 90. After removing one number, (x + y) / 2 = 25 => x + y = 50. Therefore, removed number = 90 - 50 = 40.