You are presented with 3 boxes. One of the boxes contains $300. The other 2 are empty boxes. You will win the contents of the box you choose.

Now... After you have chosen a box, one of the un-chosen boxes is opened and revealed to be empty.

You are now presented with the option of keeping your original choice or switching to the remaining box.

1) What is the EV of not switching?

2) What is the EV of switching?

3) What do you do?