UPSC Exam  >  UPSC Questions  >  The average marks of 100 students are given t... Start Learning for Free
The average marks of 100 students are given to be 40. It was found later that marks of one student were 53 which were misread as 83. The corrected mean marks are
[2019]
  • a)
    39
  • b)
    39.7
  • c)
    40
  • d)
    40.3
Correct answer is option 'B'. Can you explain this answer?
Most Upvoted Answer
The average marks of 100 students are given to be 40. It was found lat...
Solution:

Given, the average marks of 100 students = 40

Let the sum of marks obtained by 100 students be 'A'

∴ A/100 = 40

⇒ A = 4000

Now, it was found that marks of one student were misread as 83 instead of 53.

Let the correct marks obtained by that student be 'x'

∴ A + x - 83 + 53 = A + x - 30

Now, the new average is given by:

(A + x - 30)/100

⇒ (4000 + x - 30)/100

⇒ (3970 + x)/100

We need to find the corrected mean marks, which is the new average.

It is given that the corrected mean marks = 39.7

⇒ (3970 + x)/100 = 39.7

⇒ 3970 + x = 3970 + 3970/10

⇒ x = 397

Hence, the correct marks obtained by the student is 397.

Therefore, the corrected mean marks = (4000 + 397 - 53)/100 = 39.7

Therefore, the correct answer is option 'B'
Explore Courses for UPSC exam

Top Courses for UPSC

The average marks of 100 students are given to be 40. It was found later that marks of one student were 53 which were misread as 83. The corrected mean marks are[2019]a)39b)39.7c)40d)40.3Correct answer is option 'B'. Can you explain this answer?
Question Description
The average marks of 100 students are given to be 40. It was found later that marks of one student were 53 which were misread as 83. The corrected mean marks are[2019]a)39b)39.7c)40d)40.3Correct answer is option 'B'. Can you explain this answer? for UPSC 2024 is part of UPSC preparation. The Question and answers have been prepared according to the UPSC exam syllabus. Information about The average marks of 100 students are given to be 40. It was found later that marks of one student were 53 which were misread as 83. The corrected mean marks are[2019]a)39b)39.7c)40d)40.3Correct answer is option 'B'. Can you explain this answer? covers all topics & solutions for UPSC 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for The average marks of 100 students are given to be 40. It was found later that marks of one student were 53 which were misread as 83. The corrected mean marks are[2019]a)39b)39.7c)40d)40.3Correct answer is option 'B'. Can you explain this answer?.
Solutions for The average marks of 100 students are given to be 40. It was found later that marks of one student were 53 which were misread as 83. The corrected mean marks are[2019]a)39b)39.7c)40d)40.3Correct answer is option 'B'. Can you explain this answer? in English & in Hindi are available as part of our courses for UPSC. Download more important topics, notes, lectures and mock test series for UPSC Exam by signing up for free.
Here you can find the meaning of The average marks of 100 students are given to be 40. It was found later that marks of one student were 53 which were misread as 83. The corrected mean marks are[2019]a)39b)39.7c)40d)40.3Correct answer is option 'B'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of The average marks of 100 students are given to be 40. It was found later that marks of one student were 53 which were misread as 83. The corrected mean marks are[2019]a)39b)39.7c)40d)40.3Correct answer is option 'B'. Can you explain this answer?, a detailed solution for The average marks of 100 students are given to be 40. It was found later that marks of one student were 53 which were misread as 83. The corrected mean marks are[2019]a)39b)39.7c)40d)40.3Correct answer is option 'B'. Can you explain this answer? has been provided alongside types of The average marks of 100 students are given to be 40. It was found later that marks of one student were 53 which were misread as 83. The corrected mean marks are[2019]a)39b)39.7c)40d)40.3Correct answer is option 'B'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice The average marks of 100 students are given to be 40. It was found later that marks of one student were 53 which were misread as 83. The corrected mean marks are[2019]a)39b)39.7c)40d)40.3Correct answer is option 'B'. Can you explain this answer? tests, examples and also practice UPSC tests.
Explore Courses for UPSC exam

Top Courses for UPSC

Explore Courses
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev