Question

Let A = {a, b, c, d} and B = {1, 2, 3, 4}.

a) How many functions f: A -> B are there?

b) How many functions f: A -> B satisfy f(a) = 2?

Answer 1

for (a) how many choices do you have for f(a)?

Answer 2

Not sure. This is how the problem was presented.

Answer 3

and there is nothing wrong with the problem.

you should be able to figure out how many possible mapping there are for f(a)

f(a)=1
f(a)=2
f(a)=3
f(a)=4