CBSE NCERT Solutions Chapter 5 Arithmetic Progressions Exercise 5.3 Question 7
7. Find the sum of first 22 terms of an AP in which d = 7 and 22nd term is 149.
It is given that 22nd term is equal to 149.
Using formula , to find nth term of arithmetic progression, we can say that
Applying formula, to find sum of n terms of AP and putting value of a, we get
Therefore, sum of first 22 terms of AP is equal to .