Can anyone tell me how I should calculate this problem?
You are on vacation in a foreign country, and you need help. There are 50 people nearby, and you know 25% of the population of this country speaks English.
If you were to call for help:
(a) What is the probability any of them would understand?
(b) The probability that they will all understand?
(c) What's the probability that none will understand what you're saying?
I've got a feeling this falls under the realm of combinatorics but I don't know how to calculate it. A hand anyone?
This problem wasn't given by a professor, it's just a question that came up while chatting with friends and is being asked out of simple curiosity (actually to settle an argument, but...)
Also I'm not a native English speaker, so that's perhaps why the question wasn't clear enough.
For the sake of simplicity, asume the sample group is made of random people, all equally likely to speak the language or not.
My friend Jerome insists that despite what size the groups is, the chances are still 3 to 1 that no one speaks English, but I differ and gave him the example of 100 coin tosses always resulting in tails. I understand the basic of combinatorics but am in no way a maths expert. So put simply is best. You know, you don't understand it if you can't explain it simply!
Thank you all for taking the time to answer!