the family Two years ago the mean age of 40 people was 11 years. Now a person left the group and the mean age has changed to 12 years. Find the age of the person who left the group.
Answers
Answer:
1 Year
Step-by-step explanation:
Answer:
Solution :
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Given :
Statement 1 :
Two years ago the mean age of 40 people was 11 years .
⇒ So, at present the mean age will be increased by 2,.
Hence, the mean age at present will be 11 + 2 = 13 years,.
Statement 2 :
now a person left the group and the mean age is changed to 12 years,.
⇒ So, the number of people reduced by 1 & the mean changes to 12 years,.
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We know that,
Mean = \frac{Sum (of) (all) (the) (obeservations)}{total(number)(of)(observations}total(number)(of)(observationsSum(of)(all)(the)(obeservations)
⇒ \frac{Sum (of) (all) (the) (obeservations)}{40} = 1340Sum(of)(all)(the)(obeservations)=13
⇒ Sum of all the observations = 40 x 13
⇒ Sum of all the observations = 520
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Let the age of the man be x,
Then,
after he left the group,
⇒ \frac{520-x}{40-1} = 1240−1520−x=12
⇒ 39 x 12 = (520 -x)
⇒ 468 = 520 - x
⇒ x = 520 - 468
⇒ x = 52
∴ The age of the person who left the group is 52 years
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Hope it Helps !!