model 5 find new average from error Practice Questions Answers Test with Solutions & More Shortcuts

Question : 16

A student, by mistake, wrote 64 in place of 46 as a number at the time of finding the average of 10 given numbers and got the average as 50. The correct average of the numbers is :

a) 48

b) 48.2

c) 49

d) 48.1

Question : 17 [SSC CPO 2010]

In an examination, the average of marks was found to be 50. For deducting marks for computational errors, the marks of 100 candidates had to be changed from 90 to 60 each and so the average of marks came down to 45. The total number of candidates, who appeared at the examination, was

a) 300

b) 600

c) 150

d) 200

Question : 18 [SSC CGL Tier-I Re-Exam 2014]

The average marks obtained by 22 candidates in an examination are 45. The average marks of the first 10 candidates are 55 and those of the last eleven are 40. The number of marks obtained by the eleventh candidate is

a) 0

b) 45

c) 47.5

d) 50

Question : 19

The average marks of 100 students were found to be 40. Later on it was discovered that a score of 53 was misread as 83. Find the correct average corresponding to the correct score.

a) 39

b) 38.7

c) 41

d) 39.7

Question : 20

The average weight of a group of 20 boys was calculated to be 89.4 kg and it was later discovered that one weight was misread as 78 kg. instead of 87kg. The correct average weight is

a) 89.25 kg

b) 88.95 kg

c) 89.85 kg

d) 89.55 kg