Average age of 11 persons is 32 years. One
person left the group then average age
decreases by 5 years. Find age of person.
Answers
Answer:
the man who left his age was 82 yrs.
Answer:
The age of the person is 82 years.
Given:
Average age, A₁ = 32 years
Number of persons, n = 11
One person left the group and the average age decreases by 5.
New average age, A₂ = 32 - 5 = 27 years
Find:
The age of the person who left the group.
Solution:
Case I:
Number of persons, n₁ = 11
Average age, A₁ = 32 years
But average age = Sum of ages of 11 persons/Number of persons
A₁ = Sum of ages of 11 persons/n₁
Sum of ages of 11 persons = A₁n₁
Sum of ages of 11 persons = 32×11
= 352 years
Case II:
One person left the group.
Number of persons, n₂ = 10
Average age, A₂ = 27 years
But average age = Sum of ages of 10 persons/Number of persons
A₂ = Sum of ages of 10 persons/n₂
Sum of ages of 10 persons = A₂n₂
Sum of ages of 10 persons = 27×10
= 270 years
∴ Age of person who left the group = Sum of ages of 11 persons - Sum of ages of 10 persons
Age of person who left the group = 352 - 270
= 82 years
Hence, the age of the person is 82 years.
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