The average age of 30 students is 15 years. It was observed that while calculating the average age. the age of a student was taken as 15 years instead of 9 years. What will be the correct average age?

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SSC CHSL Tier-I Exam 2022 Official Paper (Held On: 09 March, 2023 Shift 1)
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  1. 14.2 years
  2. 16.4 years
  3. 15.6 years
  4. 14.8 years

Answer (Detailed Solution Below)

Option 4 : 14.8 years
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SSC CHSL Exam 2023 Tier-I Official Paper (Held On: 02 Aug 2023 Shift 1)
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100 Questions 200 Marks 60 Mins

Detailed Solution

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Given:

Number of students = 30

Average age (incorrectly calculated) = 15 years

Age of one student was incorrectly taken as 15 years instead of the actual age of 9 years.

Formula:

Correct Average Age = (Sum of all ages of students - incorrect age + correct age) / Number of students

Solution:

Sum of all ages of 30 students = 30 x 15 = 450

Incorrectly added age = 15

Correct age = 9

Therefore, the correct sum of all ages = 450 - 15 + 9 = 444

Correct Average Age = 444 / 30 = 14.8 years (approx)

Hence, the correct average age of the 30 students is 14.8 years.

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