For an integer n ≥ 2, if the arithmetic mean of all coefficients in the binomial expansion of (x+y)^2 n-3 is 16 , then the distance of the point P (2…
JEE Main 2025 — Mathematics Algebra
2025mcqmedium
For an integer n≥2, if the arithmetic mean of all coefficients in the binomial expansion of (x+y)2n−3 is 16 , then the distance of the point P(2n−1,n2−4n) from the line x+y=8 is:
Official previous-year question
Held on 4 Apr 2025 · Verified 6 Jul 2026.
Options
A
2
B
22
C
52
D
32
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Solution
No. of terms in (x+y)(2n−3)⇒[(2n−3+1)(2n−2)].∴ sum of all coefficients =22n−3 (Put x=y=1 ) ∴ Arithmetic mean of all coefficients $\begin{aligned} & =\left(\frac{2^{2 n-3}}{2 n-2}\right)=16 \ & \Rightarrow 2^{2 n-3}=2^5(n-1) \Rightarrow n=5 \ & \therefore P\left(2 n-1, n^2-4 n\right)=(9,5) \end{aligned}$
x+y=8∴PM=29+5−8=26=23×2=32
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