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# Probability watch

1. ok so here goes...

In a village of 30 people 10 support blue and 20 support red
In a sample of 10 what is the probability that exactly 7 support red

just a pointer would be good

thanks
2. How many ways of choosing a sample of 10 from 30 people?
How many ways of choosing 7 red from 20 and 3 blue from 10?
3. (Original post by DFranklin)
How many ways of choosing a sample of 10 from 30 people?
How many ways of choosing 7 red from 20 and 3 blue from 10?
so i have (30c10), (20c7) and (10c3)

so now do i do (20c7)x(10c3)/(30c10)??

so i get 0.31?
4. Yes.
5. thanks

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