Question

If numbers between $8$ and $26$ such that the resulting sequence is an AP are $11,14,17,20,x.$,then $x$ is equal to ____.

Answer 1

Common difference,

$d=\frac{b-a}{n+1}$

$=\frac{26-8}{5+1}$

$=\frac{18}{6}=3$

$a_1=a+d=8+3=11$

$a_2=a+2d=8+2\times 3=14$

$a_3=a+3d=8+3\times 3=17$

$a_4=a+4d=8+4\times 3=20$

$a_5=a+5d=8+5\times 3=23$

Numbers between $8$ and $26$ are $11,14,17,20,23$ which is in A.P.

Then $x$ is equal to $23$.