Answer
$0.917$,
$0.594$,
$0.0014$
Work Step by Step
Total outcomes of choose 5 from 20: $_{20}C_5$=15504
What is the probability that the collection will include at least one group from the United States?
Choices with none from US: $_{13}C_5$=1287,
The probability that include at least one from the US: $p=1-\frac{1287}{15504}=0.917$
At least 2 from the United States?
Choices with only 1 from the US: $_{13}C_4$*$_7C_1$=5005
The probability that at least 2 from the US: $p=1-\frac{1287+5005}{15504}=0.594$
That all 5 will be from the United States?
Choices of 5 out of 7: $_7C_5$=21
The probability that all 5 from the US: $p=frac{21}{15504}=0.0014$
