Question

The average age of a group of 50 persons is 60 years. When five persons are included to it, the average becomes 62 years. What is the average age of new persons?

Answer 1

 Simple method :

Sum of the ages of 50 persons $=50 \times 60=3000$ years

Sum of the ages of 50 persons included with 5 persons $=55 \times 62$ $=3410$ years

$\therefore \quad$ Required average age

$$

\begin{aligned}

=\frac{3410-3000}{5} &=\frac{410}{5} \\

&=82 \text { years }

\end{aligned}

$$