SOLUTION: 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

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Question 1045433: 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:
Found 2 solutions by ikleyn, stanbon:
Answer by ikleyn(52787)   (Show Source): You can put this solution on YOUR website!
.
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:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 

You are given

 -  = 2.

Here  S is the sum of ages of 19 teachers and   is the average age of 20 teachers including the retired one.

 is the average age of 20 teachers where the retired teacher's age 60 is replaced by the new teacher's age "x".

Solve for x:

 = 2,

 = 2,

60-x = 2*20 = 40,

x = 60 - 40 = 20.

Answer. The new teacher's age is 20 years.


Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
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:
==========================
Original average of the 20 teachers:: "a"
Sum of their ages = 20a
-----------------------
After one retires::
Sum of the 19 teachers ages:: 20a-60
---
Let the new teachers age be "t"
=====
Equation::
original average - new average age = 2 years
a - [20a-60+t]/20 = 2
-----
20a - 20a + 60 - t = 40
t = 20 yrs ( new teacher's age)
----------------
Cheers,
Stan H.
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