JEE Main 2024MathematicsPermutation CombinationHardNumerical

JEE Main 2024Permutation Combination Question with Solution

JEE Main 2024 (01 Feb Shift 2)

Question

The lines L1,L2,...,L20 are distinct. For n=1,2,3,...,10 all the lines L2n1 are parallel to each other and all the lines L2n pass through a given point P. The maximum number of points of intersection of pairs of lines from the set L1,L2,...,L20 is equal to:

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Show full solutionCorrect answer: 101
Correct answer
101

Step-by-step explanation

Given:

Out of 20 numbered lines, even numbered lines are concurrent, odd number lines are parallel.

So, the maximum number of intersection points will be given by,

N=1point of intersection when both lines are even+0point of intersection when both lines are parallel+C110×C110point of intersection when 1 odd and 1 even line meets

N=1+0+100

N=101

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About this question

This is a previous-year question from JEE Main 2024, covering the Permutation Combination 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.