64Digits

Another riddle :P

Posted by JaJ on June 18, 2006, 3:13 p.m.

There are 4 cards on a table. The cards have an image on both sides. This can either be a triangle, square, circle or star.

The first card has a star on the up-side

The second has a circle on the up-side

The third a triangle

The fourth a square

Someone claims that if there is a triangle on the up-side, there is a star on the down side.

How many cards do you have to flip over to check this out?

Please explain why, since there are only 5 possible answers.

Comments

Josea 18 years, 5 months ago

wait, the third has a triangle on the up side?

V 18 years, 5 months ago

wow, confusing…

Polystyrene Man 18 years, 5 months ago

Are you sure you've given the whole riddle? Couldn't you just flip two cards (the one with the triangle, and the one with the star) to check?

Vance_Kimiyoshi 18 years, 5 months ago

2, first and third.

gamerman 18 years, 5 months ago

1st the 3rd and the first 3…….

JaJ 18 years, 5 months ago

Yes, on the up-side, no right answers so far

Polystyrene Man 18 years, 5 months ago

AH! I got it! No one will ever know, because if you flip the card over then the triangle will be on the top (no longer on the bottom). You can never know what is on the bottom without prior knowledge.

Kaz 18 years, 5 months ago

Quote:

You can never know what is on the bottom without prior knowledge.

If you flip a card over the bottom is now the top. Now you know the top and bottom.

Tasm 18 years, 5 months ago

Umm…. the 3rd one…

It's the only one a triangle on the up-side, so it's the only one you need to check. If it doesn't have a star on the down-side, then that person is wrong.

Polystyrene Man 18 years, 5 months ago

Quote: Kaz

If you flip a card over the bottom is now the top. Now you know the top and bottom.

Yes, but he's saying that if there is a triangle on the upside, there will be a star on the downside. You cannot prove this because when you flip the card over, the star becomes the new upside and the triangle becomes the new downside. Therefore, there is no way to prove that there is always a star on the downside.