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Question #40565

Difficulty: 8/10 | 🟢 Free

The Question

Let SS be the set of all distinct permutations of the multiset {1,2,3}\{1, 2, 3\}. For each permutation σ=(σ1,σ2,σ3)∈S\sigma = (\sigma_1, \sigma_2, \sigma_3) \in S, a plane PσP_\sigma is defined by the equation xσ1+yσ2+zσ3=1\frac{x}{\sigma_1} + \frac{y}{\sigma_2} + \frac{z}{\sigma_3} = 1. Let QQ be the unique point of intersection of all the planes PσP_\sigma for σ∈S\sigma \in S. Let N1,N2,N_1, N_2, and N3N_3 be the number of distinct permutations of the letters of the words 'TO', 'JEE', and 'NOON' respectively. A plane Π\Pi contains the origin OO, the point QQ, and the point R(N1,N2,N3)R(N_1, N_2, N_3). A line LL lies in the plane Π\Pi, passes through the origin, and is perpendicular to the line OQOQ. If the direction ratios of LL are (a,b,c)(a, b, c) where a,b,ca, b, c are coprime integers and a>0a > 0, find the value of a2+b2+c2a^2 + b^2 + c^2.

Options

  • A.

    26

  • B.

    78

  • C.

    546

  • D.

    6

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Monster

Ultra-high difficulty questions designed to test your limit, stamina, and deep conceptual understanding.

Concepts Behind This Question

Permutations of Identical Objects|Line lying in a plane|Variable plane intercepts

Why This Question Is Tricky

Common Mistakes

This question tests the student's ability to handle a dynamically generated family of planes based on combinatorial states, coupled with 3D analytical geometry.

The primary trap lies in the variable plane intercepts: students often fail to recognize the symmetry of the permutation set, which guarantees a unique common intersection point on the line x=y=zx=y=z.

Instead, they might erroneously pick a single plane from the family (e.g., x+y/2+z/3=1x + y/2 + z/3 = 1) and proceed, leading to an incorrect direction vector.

Additionally, the problem requires precise calculation of multiset permutations and multiple cross products, punishing those who confuse the normal of a plane with a line lying within it.

Quick Facts About This Question

Question Information

SubjectMathematics
ChapterPermutations and Combinations - Class 11
ConceptPermutations of Identical Objects
Difficulty8
Cognitive Load7
Target Solve Time160 sec
AccessFree