Question

Find the common difference of the A.P created by inserting 20 A.Ms between 2 and 86.

• A. 2
• B. 3
• C. 4
• D. 5

Answer 1

The correct option is C

4

When we add 20 A.Ms between 2 and 86, the resultant A.P would look like
2,$A_1,A_2,.......A_{19},A_{20},86$

There are 22 numbers in this A.P including 2 and 86.
First term of this A.P is 2 and the last term is 86. $A_1$ is the second term and 86 is the ${22}^{nd}$ term.
$t_1=2$
$t_{22}=86$
To find the common difference,
2+(22-1)d=86
d=4