AVERAGE MCQ SET 8
1. The average of 36 numbers was found to be 45 . Later , it was detected that 84 was misread as 48 . Find the correct average of the given numbers .
(a) 58
(b) 48
(c) 46
(d) 56
Answer: C
2. The average of 45 numbers was found to be 39 . Later on , it was detected that a number 65 was misread as 56 . Find the correct average of the given numbers .
(a) 36.2
(b) 37.2
(c) 38.2
(d) 39.2
Answer: D
3. The average of 16 numbers is 35 . It was found later that four numbers 18 , 17 , 24 and 35 were taken by mistake . What is the new average after removing these numbers ?
(a) 38.83
(b) 42.33
(c) 46.66
(d) 33.33
Answer: A
4. The average of the marks of 25 students in a class , in an examination was calculated to be 19 . Later , the teacher realized that the marks of two students were taken as 18 and 19 respectively , instead of 14 and 15 . Find the new actual average marks of the class .
(a) 17.43
(b) 16.56
(c) 18.68
(d) 17.65
Answer: C
5. A student finds the average of ten 2-digit numbers . while copying numbers by mistake , he writes one number with its digits interchanged . As a result his answer is 2.7 less than the correct answer . The difference of the digits of the number , in which he made mistake is :
(a) 3
(b) 5
(c) 4
(d) 2
Answer: A
6. Average marks of 25 marks students is 40 . One student got 20 marks instead of 60 and other student got 90 marks in place of 80 . The number of student wrongly read as 25 instead 20 . Find the true average .
(a) 51.5
(b) 52
(c) 51
(d) 50
Answer: A
7. In an examination , the average marks was found to be 50 . After deducing computational errors the marks of the 100 candidates had to be changed from 90 to 60 each and the average came down to 45 marks . The total number of candidates who took the exam , were :
(a) 300
(b) 600
(c) 200
(d) 150
ย Answer: B
8. Several students have taken an exam . There was as error in the answer key which affected the marks of 48 students , and their average marks reduced from 78 to 66 . The average of remaining students increased by 3.5 marks . This resulted the reduction of the average of all students by 4.5 marks . The number of students that attended the exam is :
(a) 96
(b) 84
(c) 93
(d) 100
Answer: C
9. While finding the average marks of a class , Vikas marks were wrongly entered as 98 in place of 89 . Due to this error , the average marks of the class were 0.25 more than the actual average . What is the number of students in the class ?
(a) 32
(b) 38
(c) 34
(d) 36
Answer: D
10. A student’s marks were wrongly entered as 65 instead of 45 . Due to this , the average marks for the class got increased by 1/3 . The number of students in the class is :
(a) 40
(b) 20
(c) 60
(d) 30
Answer: C
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