Question

The average age of $45$ persons is decreased by $\frac{1}{9}$ year when one of them having $60$ years is replaced by a new comer. Then, the age of the new comer is

• A. $48$ years
• B. $46$ years
• C. $50$ years
• D. $55$ years

Answer 1

The correct option is D $55$ years

Number of persons, $N=45$
Age decreased by $=\frac{1}{9}$ years
Age of incoming $=x$ years
Age of out going $=60$ years
Now, Number of the persons in group $\times$ age decreased $=$ Difference in age between out going and incoming person.
$45\times \frac{1}{9}=60-x$
$x=60-5=55$ years.