JEE Main 2019MathematicsBinomial TheoremHardMCQ

JEE Main 2019 — Binomial Theorem Question with Solution

JEE Main 2019 (10 Jan Shift 2)

Question

If ∑r=025Cr 50C25-r 50-r=KC25 50, then K is equal to

Choose an option

Show full solutionCorrect option: A
Correct answer
A225

Step-by-step explanation

Given:

∑r=025Cr 50C25-r 50-r=KC25 50

LHS

=∑r=025 50Cr 50-rC25-r

=∑r=02550!r!50-r!50-r!25-r!25!

=∑r=025 50!  25!r!25-r!25!25!

= 50C25 ∑r=025 25Cr

= 50C25 ×225

=KC25 50

∴K=225

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About this question

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.