Question

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

(A) 30 (B) 33 (C) 37 (D) 38

Answer 1

(B) 33

Explanation:

We know that the nth term of an AP is

a_{n =} a + (n – 1)d

Where,

a = first term

a_n is nth term

d is the common difference

a_{2 =} a + d = 13 …..(1)

a_{5 =} 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

a_{7 =} a + 6d

= 9 + 6(4)

= 9 + 24 = 33