Question

In a group of $8$ boys, $2$ boys aged at $21$ and $23$ were replaced two new boys. Due to this the average cost of the group increased by $2$ years. What is the average age of the $2$ new boys?

Answer 1

$\Rightarrow$ Average of $8$ boys increased by $2$, this means the total age of boys increased by $8\times 2=16years$

$\Rightarrow$ So sum of ages of two new boys $=21+23+16=60$

$\Rightarrow$ Average age of two new boys $=\frac{60}{2}=30yeras$