50%. The fact that one is a male doesn't have any impact on the other being a male.

"Is that your final answer?"

I agree with reddwarf. How do you do the blue highlighting?

Check post #159 in this thread: http://www.digitalhome.ca/forum/showpost.php?p=729140&postcount=159

Sorry reddwarf.
You've made an error in your logical thinking. I made it too when I read the problem first time.
You've made the logical assumption that they are independent of each of other.
good luck

99gecko,

How are they not independent of each other?

Hmm, since I subscribe to this thread, I get these posts emailed to me. In the email, I see the text of the post, without the blue highlighting.

I kinda think this question has gone past the point of secrecy. If there's a debate, it's time to start.

Okay,
But I'll leave the spoiler text up for those that still want another shot at it without hints.

How about an analogy.
You go to Vegas and play roulette. Assume there are no green spots on the wheel; just 18 black and 18 red. Spin the wheel twice. What are the odds that black comes up twice?
The spins are independent of each other. However, once there is more than one spin, they become a set.

For that analogy, that makes sense. I took stats in high school. The odds of that are 1/4 (1/2 * 1/2 = 1/4). However for the original question, it wasn't asked what are the odds that both kittens would be male. The guy just wants a male kitten. The odds that the other one is male is still 50% as I said originally, one kitten's sex has no impact on the other. You could assume that the cat washer checks the cat to see what sex it is but that isn't stated in the question as you could also assume that that person already knows the sex of both kittens and doesn't need to check.

2/3

There are four cases.
FF
FM
MM
MF
The first case we can eliminate.

Since we're considering only the second cat, that leaves us with 2/3 probability.

probability always induces debate. Same as what happened with the monty hall 3 doors debate.

This is actually the same problem as the monty hall 3 door problem. Just presented differently.

JoeSoap,

You understand the concept but it is actually 1/3 probability that the 2nd cat is male as well. 2/3 probability that the 2nd cat is female.

reddwarf:
The kitten washer and pet shop owner are really irrelevent elements to this mindtwister. They are simply instruments to provide the question in a story like setting. The final question is what is important:
"what is the probability that the other one is a male?"

Q and Joesoap are correct.

For a more detailed explanation:
http://mathforum.org/library/drmath/view/52186.html

Okay, I'm going to make things fun again before I get lynched,.... this is more of joke than a brain twister:

How many kittens from the previous puzzle can you put into an empty box?

Attempt to answer kitten in box joke:
Since there were 2 kittens involved in the last brain twister you could fit 2 kittens in an empty box.

Hmmm, to complicate the previous puzzle, the chances of male and female kittens is not equal - male births are higher, but then male mortality is higher.

Chance of male birth is about 0.52.

As to new puzzle... Only one, then the box won't be empty anymore

toquewearingtechie
You are correct ! :) Congratulations for thinking outside the box (pun intended)

talljack,
While you provided an answer which I thought was very good, I can't change the correct answer just so it matches yours ;).... But kudos for reading the question carefully.

Oh well, ToqueWearingTechie answered it, I never thought about it that way ha ha.
Now how big of a box would you need to fit all the cats and kittens in from the girls backpacks on the bus riddle. ;)

Well it looks like fun but I keep getting beaten to the buzzer in Hugh's new turkey quote thread (http://www.digitalhome.ca/forum/showthread.php?t=119483) (even though it looks like a stumper has been posted) and it's been a while since we shook this thread, so here goes:



A horse and a sheep eat all the grass of a pasture in 45 days.

The horse and a goose eat the grass in 60 days.

The goose and the sheep eat the grass in 90 days.

The horse eats the same amount of grass as the goose and the sheep together.

Taking into consideration that new grass grows continuously, how long does it take the three animals together to eat all the grass??

hint below:
Simple algebra will not direct you to the answer. Pay attention to the bold word in the question

cheers.

EDIT: @talljak, Why would we even need a box? The cats and kittens are already safely secured in backpacks. ;)