12132007, 01:01 PM



Location: N of citrus, S of decent corn
16,133 posts, read 18,455,499 times
Reputation: 24491


Solve this math problem?
Last night my 6th grade grandson had the following problem: If a cat has five kittens, what is the probability that they will all be female?
Nobody knew how to arrive at the answer, including the other grandmother who taught high school math, and his mother who teaches 4th grade. His answer was 2 1/2, but who knows if it's right?

12132007, 01:10 PM



Location: San Fernando Valley, CA
1,719 posts, read 4,503,686 times
Reputation: 737


hmm, half of 5 is 2.5...and there are only two options:male/female.
I bet it isnt scientific on the probability so I'm guessing its a 50/50 question.
So 2.5 would be correct.

12132007, 01:11 PM



1,363 posts, read 4,018,984 times
Reputation: 806


This is why I was an English major

12132007, 01:18 PM



18,882 posts, read 21,149,359 times
Reputation: 26456


If the answer is a probability then it should be given as a percentage which means he told you 2 1/2 percent.
For each cat born there is a 50/50 chance it will be female (like the previous poster I have doubts about that) so a simple explanation is 5 times .5 which does give you 2.5%.
I know I got the same answer as Hungry For Cheese (Love that name!), but the logic is presented a bit differently.

12132007, 02:08 PM



Location: Western NY
43 posts, read 108,944 times
Reputation: 35


OR 
It could be 16.66%  Because there are 6 ways the delivery could happen
5 females
4 females  1 male
3 females  2 males
2 females  3 males
1 female  4 males
5 males
In which case your probability is 1/6 ...
hmm..

12132007, 02:18 PM



1,566 posts, read 2,805,451 times
Reputation: 876


3.125% chance
1/2*1/2*1/2*1/2*1/2 since each event is mutually exclusive

12132007, 02:24 PM



Location: Salt Lake City, UT
520 posts, read 1,303,939 times
Reputation: 447


Quote:
Originally Posted by truckingbronco
3.125% chance

I believe this is the correct answer. Thinking back to my engineering statistics I believe you multiply all the probabilities together. For each kitten there is a 50% chance that it is female. If there are five kittens, the probability that they are all female is (.5)(.5)(.5)(.5)(.5) = .03125.
I could be completely wrong though. I recall getting a 23% on one of the exams in that statistics class. The class average was something like 21%.
Update: This link at wikipedia explains it
http://en.wikipedia.org/wiki/Probability
Read the Mathematical Treatment section.

12132007, 02:44 PM



Location: San Fernando Valley, CA
1,719 posts, read 4,503,686 times
Reputation: 737


Whoa, i missed the part that said ALL female...it isnt 50%
It is the 3.125%...final answer. lol

12132007, 09:29 PM



Location: Mississippi
6,572 posts, read 8,370,470 times
Reputation: 3931


I really like this post. I think we should have a subforum that people can post these kinds of questions on. It can be allencompassing of every subject to include science, english, math, etc.... I think it'd be fun, and it'll also make us realize how much we've forgotten since school.

12142007, 10:17 AM



Location: Minnesota
206 posts, read 354,785 times
Reputation: 81


.03125 or 3.125% as others have said.
I knew the rule for this one off the top of my head, though I tended to get some of my worst grades in math.

Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.
Detailed information about all U.S. cities, counties, and zip codes on our site: Citydata.com.

