Question

3. Let A = {1, 2, 3, 4, 5}, B = 2, 3, 6, 7). Then the number of elements in
(A x B) n (B x A) is
A 18
B. 6.
C. 4
D. O​

Answer 1

Answer:

c . 4

Step-by-step explanation:

A×B = { (1,2),(1,3),(1,6),(1,7),(2,2),(2,3),(2,6),(2,7),(3,2),(3,3),(3,6),(3,7),(4,2),(4,3),(4,6),(4,7),(5,2),(5,3),(5,6),(5,7)}

B×A = {(2,1),(2,2),(2,3),(2,4),(2,5),(3,1),(3,2),(3,3),(3,4),(3,5),(6,1),(6,2),(6,3),(6,4),(6,5),(7,1),(7,2),(7,3),(7,4),(7,5)}

So,

(A×B)n(B×A) = {(2,2),(2,3),(3,2),(3,3)}

so total number of elements is 4