Question

If the 7^th term of a HP is 1/10 and the 12^th terms is 1/25, then the 20^th term is

(a)  1/37

(b)  1/41

(c)   1/45

(d)  1/49

Answer 1

Correct option  (d)  1/49

First term of an AP = 10 and the 12^th term = 25. Considering corresponding AP 

a + 6d = 10 and a + 11d = 25 d = 3,a = -8

⇒ T₂₀ = a + 19d = 8 + 57 = 49

Hence, the 20^th term of the corresponding HP is 1/49.