it’s calculated as follows:
wanted ones divided by possible ones.
then you have to multiply the results of each time you drew.
first draw: 1/4
second draw: 1/3
1/4 * 1/3 = 1/12
1/12 is the result.
That includes duplicates though, right? ie 1 & 2 vs 2 & 1
jtnw
actually the likelihood of them being the same (without regard for one color or the other) is 1/3, had you asked what is the likelihood of them both being red, then it would have been 1/12th. As the question is asked the first card doesn’t really count, as it just determines what the other card has to be in order to match.
Paradox is right. The answer is 1/3. Lots of people say 1/4 or 1/2.
You can do the same with children. If a couple have two children and one of them is a boy, what is the likelihood that the other is a boy as well. That answer is 1/3 as well.
nother one fer u fellas
A man is wearing black. Black shoes, socks, trousers, jumper,
gloves, and balaclava. He is walking down a black street
with all the street lamps off. A black car is coming toward him
with its lights off too, but somehow manages to stop in time. How
did the driver see the man?
It’s daytime. 
jtnw
He didn’t, the man was walking on the sidewalk and was never in any kind of danger… duh :sigh:
nice one how did you noe jtnw
arrite another one for you peeps
How would you rearrange the letters in the words new door to make one
word? Note: There is only one correct answer.
azzy, I’ve heard most of these before. I know the new door one, but I’ll let others have a chance at it.
jtnw
Just arrange them and make “one word”?
as in “new door” —> arranges ----> “one word” :beam:
:bad:
ding ding ding we have a winner
No it’s not, it’s 1/2 
It’s either a boy or a girl.
arrite men heres another one.
three ants were going under a door and two or them could pass by. why coudnt the third one go
Someone opened the door 
I didn’t understand the sentence in the first place :ne:
no you silly the third ant was wearing high heel sandals
because it was really really fat?
because it had claustrophobia?
=)
The trick is in the wording. If you said ‘If the first child is a boy, what is the chance that both of the children are boys?’, then the answer is 1/2.
But when you say ‘If one of the children is a boy, what is the chance that both the children are boys?’, then the answer is 1/3.
There are four equally likely combinations that you can have 2 children.
- first child is a boy, second child is a boy
- first child is a boy, second child is a girl
- first child is a girl, second child is boy
- first child is a girl, second child is girl
In three of the combinations, one of the children is a boy (1, 2 and 3). But only in one of the three (no. 1) are both children boys. So the answer is 1/3.
I have a mate that still - after several years - insists that the answer is 1/2 
I insist it to be 1/2 as well!
the 2nd and the 3rd are identical! IF you have 1 boy then the next one can be either a boy or a girl… it doesn’t matter if the boy is the “first” or the “second” one.
ok…
If the “first” one is a boy then you’re left with variants 1 and 2 (SEE? only 2!), if the boy is the “second” one then you’re left with varianbts 3 and 1 (oh look! 2 again!) … so the answer is definitely 1/2 
Nice one Very tricky.
Here’s one of my favorite:
I have 5 hats in my hands. 3 of them are white, 2 of them are black. In front of me are standing Senocular, Kirupa and Lostinbeta. I put one hat on each head, so that they can see the color of the other people’s hat but not their own. I ask them what the color of their hat is.
Senocular, seeing a white hat on Kirupa’s head and a white hat on Lost’s head, and noticing that neither of them can answer the question, says “I’m wearing a white hat”. Now how did he know that ?
PS: This brain teaser assumes that Senocular is a bit more clever than his 2 contestants :love:
um, you’re still holding the 2 black hats and sen notices that? =)
