Question

The 10th and 18th terms of an A.P. are 41 and 73 respectively. Find the 31st term. *​

Answer 1

Answer:

Let the first term be a and common difference be d then

a

10

=41⇒a+9d

a

10

=73⇒a+17d

⇒a+9d+8d=73

⇒41+8d=73

⇒8d=73−41

⇒8d=32⇒d=4.

∴a+9d=41

⇒a+9×4=41

⇒a=5

Hence,

The 26

th

term =a+25d⇒5+25×4⇒105.

This is the required answer.