दो कक्षाओं A और B में क्रमशः 25 और 30 विद्यार्थी हैं । कक्षा-A में अधिकतम प्राप्तांक 21 है तथा न्यूनतम प्राप्तांक 17 है । कक्षा-B में अधिकतम प्राप्तांक 30 है तथा न्यूनतम प्राप्तांक 22 है । कक्षा-A से 4 विद्यार्थी कक्षा-B में स्थानांतरित किए जाते हैं ।
निम्नलिखित कथनों पर विचार कीजिए :
- 1.कक्षा-B का औसत प्राप्तांक निश्चित रूप से घटेगा ।
- 2.कक्षा-A का औसत प्राप्तांक निश्चित रूप से बढ़ेगा ।
उपर्युक्त कथनों में से कौन-सा/कौन-से सही है/हैं ?
Read this question in English
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
उत्तर और व्याख्या · explanation in English
Answer: (a) केवल 1
Every shifted student scored at most 21, below Class-B's lowest score of 22, so Class-B's average must fall. Class-A's average can rise or fall depending on which four students leave, so statement 2 is not certain.
- Each shifted student scored at most 21; every Class-B student scored at least 22.
- Adding scores lower than all existing scores pulls Class-B's average down — statement 1 is certain.
- Class-A's new average depends on whether the four who left were above or below Class-A's average.
- If the four scored 21 each, Class-A's average falls; if they scored 17 each, it rises — so statement 2 is not definite.
- ✓ 1. New members all score below Class-B's minimum, so its average must decrease.
- ✗ 2. Removing students raises the average only if they were below it; the data do not say which four moved.
Remember · Adding values below every existing value lowers the mean; removing values changes it only relative to the current mean.
Question and answer: UPSC's official GS Paper II (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·