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Friday, 9 October

JEE Main Maths · Permutations and Combinations

Pascal's Rule and nCr Properties

Pascal's Rule and nCr Properties (Permutations and Combinations) was asked 2 times in 2 JEE Main shifts, 2024, out of the 42 shifts Lumi analysed.

Times asked
2
in 2 shifts
Years
2024
Usual format
Single correct
Calculation
Pattern
New since 2024
repeats across shifts

How it is asked

  • Combinatorial inequality and permutation ratio equations
  • Find n and r from ratio of ncr

Difficulty

Easy 0Medium 2Hard 0

Where it sits

Chapter: Permutations and Combinations. Topic: Permutations and Combinations, 50 questions over 22 ideas.

Other repeat ideas in this topic

Every time it came

All 2 questions

Newest first, each with its options and official answer.

  1. 6 Apr 2024, Shift 2 · Q6Let 0≤r≤n0\le r\le n. If n+1Cr+1:nCr:n−1Cr−1=55:35:21^{n+1}C_{r+1}:{}^{n}C_r:{}^{n-1}C_{r-1}=55:35:21, then 2n+5r2n+5r is equal to :MediumSingle correct
  2. 31 Jan 2024, Shift 2 · Q6If for some m,nm,n; 6Cm+2(6Cm+1)+6Cm+2>8C3{}^6C_m+2\left({}^6C_{m+1}\right)+{}^6C_{m+2}>{}^8C_3 and n−1P3:nP4=1:8{}^{n-1}P_3:{}^nP_4=1:8, then nPm+1+n+1Cm{}^nP_{m+1}+{}^{n+1}C_m…MediumSingle correct