Question

The number of onto functions from A = {a, b, c} to B = {1, 2, 3, 4} is __________.

Answer 1

Given: A function from A = {a, b, c} to B = {1, 2, 3, 4}

If a function from A to B is onto, then number of elements of A ≥ number of elements of B.

But here, number of elements of A < number of elements of B

Thus, no onto function exist from A = {a, b, c} to B = {1, 2, 3, 4}.

Hence, the number of onto functions from A = {a, b, c} to B = {1, 2, 3, 4} is 0.