Question

If you have a finite arithmetic sequence, the first number is $2$ and the common difference is $4$, what is the $5^{th}$ number in the sequence?

• A. $6$
• B. $10$
• C. $14$
• D. $18$

Answer 1

The correct option is D $18$

A sequence of the type $a,a+d,a+2d,a+3d$ is said to form an finite A.P.
Where $a=$ first number $=2$
$d=$ common difference $=4$
Then the general form of finite A.P. $=2,6,10,14,18$
So, $18$ is the fifth number in the finite arithmetic sequence.