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UPSC Prelims

Mathematics

Theme:

Average / औसत

Q37 2021, Average

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?

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?

Explanation Please wait..

Average = Sum of participants/ number of participants.

Since the average of students of Class-A is lower than Class-B, when the 4 students will move they will reduce the average of the Class-B as the number of participant will increase but sum will not increase by much. Thus statement 1 is correct.

If the 4 student moved to other class were of lower range of score, then the average of the Class-A will increase. If the one’s that move will be of higher range, then the average will reduce. Thus, we cannot be sure of the average of Class-A.

व्याख्या Please wait..

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