Question

If two sets A and B are having 43 elements in comman, then the number of elements common to each of the sets A x B and B x A is

(a) 43² 

(b) 2⁴³ 

(c) 43⁴³ 

(d) 2⁸⁶

Answer 1

The correct option (a) 43²

Explanation:

n((A x B) ∩ (B x A)) = n((A ∩ B) x (B ∩ A)) 

= n(A ∩ B) . n(B ∩ A) 

= 43 x 43 = 43²