3 part puzzle

Originally posted by ddebened
Then I assume this puzzle has been posted elsewhere...can I at least get a link to it to satisfy my now enormous curiosity? Thanks.

Three cups, one of them covers a ball. YOu pick a cup.

Someone else then lifts a cup, one that doesn't cover the ball.

You are presented with a choice:

Switch cups or keep with the one you chose in the first place.

Originally posted by TheMaster37
Three cups, one of them covers a ball. YOu pick a cup.

Someone else then lifts a cup, one that doesn't cover the ball.

You are presented with a choice:

Switch cups or keep with the one you chose in the first place.

Some assumptions have to be made:

1)This "someone else" had to lift a cup.
2)This "someone else" knows where the ball is.
3)This "someone else" will never lift a cup containing the ball.