Skip to content
dronacharya.ai
← JEE Main 2026 · 2 Apr · Shift 2
MathematicsInteger+4 / -1Question 21 of 75

JEE Main 2026 · 2 Apr · Shift 2, Mathematics question 21

Let A={2,3,4,5,6}A=\{2,3,4,5,6\}. Let R be a relation on the set A×AA\times A given by (x,y) R (z,w)(x,y)\,R\,(z,w) if and only if xx divides zz and y≤wy\le w. Then the number of elements in R is ________.

Answer and worked solution

Official answer: 120

Count the two parts separately.

  • Pairs (x,z)(x,z) with x∣zx\mid z in {2,…,6}\{2,\dots,6\}: x=2x=2: 3; x=3x=3: 2; x=4,5,6x=4,5,6: 1 each. Total 8.
  • Pairs (y,w)(y,w) with y≤wy\le w: (52)+5=15\binom52+5=15.

Total 8×15=1208\times15=120.

Answer: 120

Topics:Relations