JEE Main 2019 — Binomial Theorem Question with Solution
From: JEE Main 2019 (Online) 11th January Morning Slot
Question
The value of r for which 20Cr 20C0 + 20Cr1 20C1 + 20Cr2 20C2 + . . . . .+ 20C0 20Cr is maximum, is
Choose an option
Show full solutionCorrect option: A
Correct answer
A20
Step-by-step explanation
Given sum = coefficient of xr in the expansion of
(1 + x)20(1 + x)20,
Which is equal to 40Cr
It is maximum when r = 20
(1 + x)20(1 + x)20,
Which is equal to 40Cr
It is maximum when r = 20
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This is a previous-year question from JEE Main 2019, covering the Binomial Theorem 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.