NDA 2019 Maths · Mathematics · Sequences and Series · easy

The 10th term of the harmonic progression 1/2,1/5,1/8,… is

Single correct option

The

10

th term of the harmonic progression

\dfrac12,\dfrac15,\dfrac18,\ldots

Show answer and solution

Answer: (C) $\dfrac1{29}$

The reciprocals

2,5,8,\ldots

form an AP with

a=2

and

d=3

. The

10

th term of this AP is

2+9\times3=29

, so the

10

th term of the HP is

\dfrac1{29}

. The option

29

forgets to take the reciprocal, while

\dfrac1{32}

uses

10d

instead of

9d

Original question written in the NDA 2019 Maths pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake