Question

Encyclopedia Britannica's list of 20 World Class Orchestras include the following from the United States: Boston Symphony Orchestra, Cleveland Orchestra, Chicago Symphony Orchestra, Los Angeles Philharmonic, New York Philharmonic, Philadelphia Orchestra, and the San Francisco Symphony. Choose 5 at random from the list of 20 for a benefit CD.
What is the probability that the collection will include at least one group from the United States?
At least 2 from the United States?
That all 5 will be from the United States?

It's a question with 3 different parts. Please explain how you did it. :)

Answer 1

Answer:

Using multiplication rule

Total=20

Probability that collection will include atleast one group from the united sates=2/20*3/20

Probability=0.15

Answer 2

Given: 

1. Boston Symphony Orchestra,
2. Cleveland Orchestra,
3. Chicago Symphony Orchestra,
4. Los Angeles Philharmonic,
5. New York Philharmonic,
6. Philadelphia Orchestra,
7. San Francisco Symphony

The probability that it will include at least one group from the US:

5/20 *7/20 = 0.0875

The probability that all 5 will be from the US:

7/20 = 0.35