 # RS Aggarwal Solutions Class 9 Mathematics Solutions for Mean Median And Mode Of Ungrouped Data Exercise 18A in Chapter 18 - Mean Median And Mode Of Ungrouped Data

Question 20 Mean Median And Mode Of Ungrouped Data Exercise 18A

The mean of 150 items was found to be 60. Later on, it was discovered that the values of two items were

misread are 52 and 8 instead of 152 and 88 respectively. Find the correct mean.

It is given that

Mean of 150 items = 60

So the total sum = 150 (60) = 9000

We know that

Correct sum of items = sum of 150 items – sum of wrong items + sum of right items

By substituting the values

Correct sum of items = 90000 – (52 + 8) + (152 + 88)

On further calculation

Correct sum of items = 9000 – 60 + 240

So we get

Correct sum of items = 9180

So the correct mean = correct sum of items/ total number of items

By substituting the values

Correct mean = 9180/150 = 61.2

Therefore, the correct mean is 61.2.

Related Questions

Lido

Courses

Teachers

Book a Demo with us

Syllabus

Maths
CBSE
Maths
ICSE
Science
CBSE

Science
ICSE
English
CBSE
English
ICSE
Coding

Terms & Policies

Selina Question Bank

Maths
Physics
Biology

Allied Question Bank

Chemistry
Connect with us on social media!