# Which term of the AP : 3, 8, 13, 18, . . . ,is 78?

**Solution:**

The formula for n^{th} term of an AP is a_{n} = a + (n - 1) d

The given arithmetic progression is 3, 8, 13, 18, ...

First term: a = 3

Second term: a + d = 8

Common difference: d = 8 - 3 = 5

a_{n} = a + (n - 1) d = 78

3 + (n - 1) 5 = 78

5(n - 1) = 78 - 3

n - 1 = 15

n = 16

Answer: 78 is the 16^{th} term of AP.

**Video Solution:**

## Which term of the AP : 3, 8, 13, 18, . . . ,is 78?

### NCERT Solutions Class 10 Maths Chapter 5 Exercise 5.2 Question 4 - Chapter 5 Exercise 5.2 Question 4:

Which term of the AP : 3, 8, 13, 18, . . . ,is 78?

78 is the 16^{th} term of AP 3, 8, 13, 18, ...