Question

If the 2^nd term of an AP is 13 and the 5^th term is 25, what is its 7^th term?

विकल्प

• 30

• 33

• 37

• 38

Answer 1

33

Explanation:

We know that the n^th term of an AP is

a_n = a + (n – 1)d

Where,

a = first term

a_n is n^th term

d is the common difference

a₂ = a + d = 13   ...(1)

a₅ = a + 4d = 25  ...(2)

From equation (1) we have,

a = 13 – d

Using this in equation (2), we have

13 – d + 4d = 25

13 + 3d = 25

3d = 12

d = 4

a = 13 – 4 = 9

a₇ = a + 6d

= 9 + 6(4)

= 9 + 24

= 33