How do I solve this?

[Dyne]

Aha! My Discrete and Combinational Math Teacher just did this yesterday!

We had 23 people in our class, and he said it's a half-half probability that two people had the same birthday.

And two people did. It blew my mind.

As for answering the question, don't use a calculator. Use the computer! I'm very sure that programs called Python or Maple would be able to calculate those.