# The average age of a class of 12 students is 24. What is the average age of class when two students of age 22 and 23 leave the class?

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The average age of a class of 12 students is 24. What is the average age of class when two students of age 22 and 23 leave the class?
1. 22.05 yrs
2. 24.3 yrs
3. 27.5 yrs
4. 26 yrs

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Correct Answer - Option 2 : 24.3 yrs

Given:

Total student = 12

Average age = 24 years

The age of the student who left the class = 22 and 23 years

Formula used:

Average = The sum of all student age/Total number of student

Calculation:

Average = The sum of all student age/Total number of student

⇒ 24 = The sum of all student age/12

⇒ The sum of all student age = 288

According to the question,

The sum of the ages of student who left the class = 22 + 23

⇒ The sum of the ages of student who left the class = 45

Now,

The age of remaining students = 288 - 45

⇒ The age of remaining students = 243

The number of remaining student = 10

New average,

Average = 243/10

⇒ Average = 24.3

∴ The new average of the class is 24.3 years.