JEE Main 2025 — Binomial Theorem Question with Solution
JEE Main 2025 (28 Jan Shift 2)
Question
Let the coefficients of three consecutive terms and in the binomial expansion of be in a G.P. and let be the number of all possible values of . Let be the sum of all rational terms in the binomial expansion of . Then is equal to :
Choose an option
Show full solutionCorrect option: A
Correct answer
A
Step-by-step explanation
Coefficient of
$\begin{aligned}
& T_r, T_{r+1}, T_{r+2} \rightarrow G P \\
& \Rightarrow\left({ }^{12} C_r\right)^2={ }^{12} C_{r-1} \cdot{ }^{12} C_{r+1}
\end{aligned}$
but no three consecutive binomial coefficient are in
GP
Now for
for rational terms
sum of rational terms
$\begin{aligned}
& ={ }^{12} \mathrm{C}_0 4^0 \cdot 3^3+{ }^{12} \mathrm{C}_{12} \cdot 4^4 \cdot 3^0 \\
& =27+256=283=q \\
& \therefore p+q=283
\end{aligned}$
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This is a previous-year question from JEE Main 2025, 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.