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

Polystyrene Man 18 years, 5 months ago

Quote: SpenSer.45
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.
No! Because if the star was on the downside, then when it was flipped it became the new upside. This cannot be proven. It's not possible. I think I have this one in the bag…

HeroofTime55 18 years, 5 months ago

its definately 1 card, the one with the triangle. The one with the star wouldnt work, there might be something ELSE that has a star on the other side. But the statement implies that a card with a triangle will ALWAYS have a star on the other side.

Playing with words making upside downside and what not has no logical effect on the problem.

NO WAIT i got it: You dont need to 'flip' any, you can lift the triangle straight up and look underneath to see whats there :P

Polystyrene Man 18 years, 5 months ago

Yeah, all you need is a glass table.

Did you make this riddle up yourself?

JaJ 18 years, 5 months ago

Yep, only one card, the triangle.

The card doesn´t change when you flip it, so Polystyrenes theory is a bit too far tought trough. Also, the person states this while looking at the start situation, when he hasn´t flipped anything yet.

We where talking about `logic´ during Mathematics and the teacher brought this problem up.

frenchcon1 18 years, 2 months ago

all of them-you cant be sure if theyre tellign the truth