Solution: We are given that there are three kindergartners and five first-graders.
We have to find the probability that at least one of them is a kindergartner.
We know that:
P(at least one kindergartner) = 1 - P(no kindergartner) = 1 - P(all first-graders)
Now, P(all first-graders)[tex]=\frac{5}{8} \times \frac{4}{7}=\frac{5}{14}[/tex]
Therefore, P(at least one kindergartner) [tex]=1-\frac{5}{14}[/tex]
[tex]=\frac{14-5}{14}=\frac{9}{14}=0.643[/tex]