Question

The mean of $10$ observation is $20$ and sum of first $5$ observations among the $10$ observation is $50$.Find mean of remaining next $5$ observations ?

Answer 1

Let the addition of first $5$ observation be a and next $5$ be b.

$\therefore a=50$

And mean $=20$

$\therefore \frac{a+b}{10}=20$

$a+b=200$

$b=200-9$

$b=200-50$

$b=150$

$\therefore$ mean of remaining $5$ observations is given by $\frac{b}{5}=\frac{150}{5}=30$.