Question

Insert three arithmetic means between $8$ and $24$.

Answer 1

We need to insert three arithmetic means between $8$ and $24$.

We know $a_n=a_1+(n-1)d$
$\Rightarrow 24=8+(5-1)d$
$\Rightarrow 24-8=4d$
$\Rightarrow 16=4d$
$\Rightarrow d=4$
Now, insert the terms using $d$.
Therefore, the series is $8,12,16,20,24$.