2n boys are randomly divided into two subgroups containing n boys each. The probability that the two tallest boys are in different groups is:
Answer & explanation
Correct answer: option 1
P(two tallest are in different groups) = $\frac{{^{2n-2}C}_{n-1}.{^2C}_1}{{^{2n}C}_n}=\frac{n}{2n-1}$