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# Mean of 100 Observations is 40. the 9th Observation is 30. If this is Replaced by 70 Keeping All Other Observations Same, Find the New Mean. - Algebra

ConceptMeasures of Central Tendency

#### Question

Mean of 100 observations is 40. The 9th observation is 30. If this is replaced by 70 keeping all other observations same, find the new mean.

• 40.6

• 40.4

• 40.3

• 40.7

#### Solution

We have,
Mean of 100 observations is 40.
Total sum of observations = 100 x 40 = 4000
If the 9th observation is 30 and is replaced by 70 keeping all other observations same.
New, total sum of observations = 4000 - 30 + 70 = 4040
So, the new mean = 4040/100 = 40.4
Hence, the correct alternative answer is (B).
Is there an error in this question or solution?

#### APPEARS IN

Balbharati Solution for Balbharati Class 9 Mathematics 1 Algebra (2019 to Current)
Chapter 7: Statistics
Problem Set 7 | Q: 1.07 | Page no. 126
Solution Mean of 100 Observations is 40. the 9th Observation is 30. If this is Replaced by 70 Keeping All Other Observations Same, Find the New Mean. Concept: Measures of Central Tendency.
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