Question

The average of $13$ numbers is $24$. If $3$ is added to each number. What will the change in new mean?

Answer 1

Let the sum of all the numbers be $s$

$24=\frac{s}{13}\Rightarrow s=312$

Now as we add 3 to each number

New Sum $=312+3\times 13=351$

New mean $=\frac{351}{13}=27$

Change in mean $=27-24=3$