Originally Posted by

**Truthbetold** Let's give names to the people just for easier reference: Dad, Mom, Kid 1, kid 2, kid 3. Let's say Dad picks first.

There is a 4/5 chance he will NOT pick his name.

Next mom picks.

There is a 3/5, because one name that is NOT dad's is gone, she won't pick name.

Then kid 1 and kid 2 pick.

There probability is 2/5 and 1/5, respectively.

NOw Kid 3 picks.

There is only one name left, here is where I'm not sure about this anymore, that is not his. So 1/5.

Finally,

multiply them together because they are dependent events.