JEE Main 2020 — Sequences And Series Question with Solution
From: JEE Main 2020 (Online) 3rd September Evening Slot
Question
If m arithmetic means (A.Ms) and three
geometric means (G.Ms) are inserted between
3 and 243 such that 4th A.M. is equal to 2nd
G.M., then m is equal to _________ .
Enter your answer
Show full solutionCorrect answer: 39
Correct answer
39
Step-by-step explanation
Given m arithmetic means (A.Ms) present between 3 and 243
Common difference,
4th A.M. = a + 4d
= 3 + 4
Also there are 3 G.M between 3 and 243
Common ratio (r) =
where n = number of G.M inserted.
r =
Given,
4th A.M = 2nd G.M
Common difference,
4th A.M. = a + 4d
= 3 + 4
Also there are 3 G.M between 3 and 243
Common ratio (r) =
where n = number of G.M inserted.
r =
Given,
4th A.M = 2nd G.M
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This is a previous-year question from JEE Main 2020, 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.