Exams › JEE Main › Maths
Let A = {1, 2, 3, 4, 5} and B = {2, 3, 6, 7}. Find the number of elements in the set (A × B) ∩ B × (B × A).
- 18
- 6
- 4
- 0
Correct answer: 4
Solution
(A×B)∩(B×A) consists of pairs (x,y) with x,y in both A and B, i.e. in A∩B = {2,3}. So the count is |A∩B|^2 = 2^2 = 4.
Related JEE Main Maths questions
- Let A be the set {(n, 2n): n ∈ N} and let B be the set {(2n, 3n): n ∈ N}. What is the intersection A ∩ B?
- Let set A contain 3 elements and set B contain 6 elements. Then the cardinality of their union must satisfy
- Given the sets A = {1, 2, 5} and B = {3, 4, 5, 9}, what is A ∩ B?
- At a conference with 100 attendees, 29 are Indian women and 23 are Indian men. Among the Indian attendees, 4 are doctors, and 24 are either men or doctors. If there are no foreign doctors, how many foreigners and how many women doctors are present at the conference?
- Let X and Y be two non-empty sets, and let A be a non-empty set such that X ∩ A = Y ∩ A = A and X ∪ A = Y ∪ A. Which of the following must be true?
- If A and B are non-empty sets with A containing B, then which of the following is true?
⚔️ Practice JEE Main Maths free + battle 1v1 →