Q. 104.8( 4 Votes )

The mean of 5 numbers is 20. If one number is excluded their mean is 15. Then the excluded number is
A. 5

B. 40

C. 20

D. 10

Answer :

Given that, Total number of observations = 5

Mean = 20


So, Sum of observations can be given as


Sum of observations = Mean × Total number of observations [ ]


Sum of observations = 20 × 5


Sum of observations = 100


Let the excluded number be x.


New Sum of observations = 100 – x


New Mean = 15


New total number of observations = 4


Mean is given by




100 – x = 15 × 4


100 – x = 60


x = 100 – 60 = 40


The excluded number is 40.


Thus, option (B) is correct.

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Quiz | Median and ModeQuiz | Median and ModeQuiz | Median and Mode29 mins
Quiz | Basics of  MeanQuiz | Basics of  MeanQuiz | Basics of Mean37 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
caricature
view all courses