Question

Let A = {1, 2} and B = {3, 4}. Find the total number of relations from A into B.

Answer 1

Given as

A = {1, 2}, B = {3, 4}

n (A) = 2 (The number of elements in set A).

n (B) = 2 (The number of elements in set B).

As we know,

n (A × B) = n (A) × n (B)

= 2 × 2

= 4 [Since, n(x) = a, n(y) = b. The total number of relations = 2^ab]

Thus, number of relations from A to B are 2⁴ = 16.