Q. There are two Classes A and B having 25 and 30 students respectively. In Class-A the highest score is 21 and lowest score is 17. In Class-B the highest score is 30 and lowest score is 22. Four students are shifted from Class-A to Class-B.
Consider the following statements:
1. The average score of Class-B will definitely decrease.
2. The average score of Class-A will definitely increase.
Which of the above statements is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Correct Answer: (a) 1 only
Question from UPSC Prelims 2021 CSAT Paper
Explanation :
Class A and Class B Student Scores
There are two Classes A and B having 25 and 30 students respectively. In Class-A, the highest score is 21, and the lowest score is 17. In Class-B, the highest score is 30, and the lowest score is 22. Four students are shifted from Class-A to Class-B.
The average score of Class-B will definitely decrease because the highest possible scores of the four students shifted from Class-A (21) are lower than the lowest score in Class-B (22).
However, we cannot say for certain that the average score of Class-A will definitely increase because it depends on which four students were shifted from Class-A to Class-B.
