Probability (A doubt to clarify)?

Question

This Is An Example Given In The Book:

Let

S = { 11, 2, 3, 4, 5, 6, 7, 8, 9, 10 }

If A = { 1, 2, 3, 4, 5, 6 }

B = { 5, 6, 7, 8, 9, 10 }

Then A U B = S [This part I don't understand, how A U B = S? there isn't a 11 in B or A... How Can A U B = S? ..]

and A and B are exhaustive events.

Thank you.

Answer 1

It's a typo, the first element in S should be "1", not "11".

Answer 2

I agree with you. It must be a mistake in the book.

Answer 3

throw away that book