Question

If 5th term of an HP is 1/45 and the 11^th terms is 1/69, then its 16^th terms will be

(A)  1/89 

(B)  1/85 

(C)  1/80 

(D)  1/79

Answer 1

Correct option (A) 1/89

Here 5^th term of the corresponding AP is

a + 4d = 45   ....(1)

and 11^th term of the corresponding AP is

a + 10d = 69  .....(2)

From Eqs. (1) and (2), we get a d = 29,d = 4. Therefore, 6th term of the corresponding AP is

a + d = 15 = 29 + 15 x 4 = 89

Hence, 16^th term of the HP is 1/89