JEE Main 2016MathematicsSequences and SeriesEasyMCQ

JEE Main 2016 — Sequences and Series Question with Solution

JEE Main 2016 (03 Apr)

Question

If the 2nd, 5th and 9th terms of a non-constant arithmetic progression are in geometric progression, then the common ratio of this geometric progression is

Choose an option

Show full solutionCorrect option: D
Correct answer
D43

Step-by-step explanation

Let the A.P. be a, a+d, a+2d, .....

Given, a+d.a+8d=a+4d2

a2+9ad+8d2=a2+8ad+16d2

8d2-ad=0

d8d-a=0

∵ d ≠0

d=a8

So, 2nd term, 5th term, 9th term

would be a+a8, a+a2, a+a

9a8, 3a2, 2a 

Common Ratio =2nd term1st term=3a×82×9a =43

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About this question

This is a previous-year question from JEE Main 2016, covering the Sequences and Series chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.