Question

If set A = {1, 2, 3} and set B = {2, 3, 5, 7}. Find the number of elements in A $\times$ B.

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Answer 1

Number of element in A $\times$ B = number of element in A $\times$ number of element in B.

= 3 $\times$ 4 = 12

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

No of element in A $\times$ B = 12