JEE Main 2017MathematicsSequences and SeriesHardMCQ

JEE Main 2017 — Sequences and Series Question with Solution

JEE Main 2017 (02 Apr)

Question

For any three positive real numbers a, b and c. If 925a2+b2+25c2-3ac=15b3a+c. Then

Choose an option

Show full solutionCorrect option: B
Correct answer
Bb, c and a are in A.P.

Step-by-step explanation

225a2+9b2+25c2-75ac-45ab-15bc=0

⇒  215a2+3b2+5c2-15a5c-15a3b-3b5c=0 

⇒  215a2+23b2+25c2-215a5c-215a3b-23b5c=0

⇒15a-3b2+3b-5c2+5c-15a2=0

⇒15a-3b=3b-5c=5c-15a=0

⇒15a=3b=5c

⇒  a1=b5=c3=k

⇒   a=k, b=5k, c=3k

⇒  a, c, b are in A.P.

⇒  b, c, a are in A.P.

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About this question

This is a previous-year question from JEE Main 2017, 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.