Question

A school has 20 teachers, one of them retires at the age of 60 years and a new teacher replaces him, this change reduces the average age of the staff by 2 years, the age of new teacher is

• A. 28 years
• B. 25 years
• C. 20 years
• D. 18 years

Answer 1

Answer: (C)

20 years

Let the average age of the staff is x year

Age of the new teacher is y year

According to the question

New average age of the staff is reduced by 2 years.

$\therefore \frac{20x-60+y}{20}=x-2$

$\Rightarrow 20x-60+y=20x-40$

$\Rightarrow y=60-40$

$\Rightarrow y=20years$

$\therefore$The age of the new teacher is 20 years.