JEE Main 2026 Mathematics question
Let A = {2, 3, 4, 5, 6}. Let R be a relation on the set A × A given by (x, y)R(z, w) if and only if x divides z and y ≤ w. Then the number of elements in R is .
Answer: 120
Solution
The count factorises: (number of pairs with x|z) × (number of pairs with y ≤ w) = 8 × 15 = 120.