Basic Probability

#1
I need some help getting started with this question.....

There N quantity of tourists on a bus and there are n quantity of children amongst them.

When the bus stopped m tourists got off. Please find the probability of that thing, that amongst m tourists that got off there are k children.

Tourists N=12
Children n=8

Number of tourists m who got off the bus = 4
Number of children k who got off bus = 3

I have real difficulty in actually understanding the question.... Can anybody please help me?
 
#2
Hi,
You have 8 children and 4 adults on a bus. 4 people get off the bus.
What is the probability that 3 of the 4 are children?

Ignoring the order for a moment,
think about the first person to get off the bus. What is the probability that it is a child? What's the probability that a second child gets off? Calculate the probability that 3 children and then 1 adult get off the bus.

Now, the order they get off the bus doesn't matter, so you have to multiply by the number of ways of picking 3 out of 4. This is the same as the number of combinations of 1 out of 4.

Hope this helps! :)
 
#3
Thank you Statstatic,

You make it sound quite so simple...... My biggest problem is actually understanding the English containred in the question.

Your help is really appreceiated.