Advanced Algebra
posted by Juan .
Sam and David are among 5 students who have a chance to win a free airline ticket to San Diego. 2 students from the group will be selected at random to win a ticket. What is the possibility that the 2 students selected will be Sam and David?

Number of ways
C(5,2) [five choose 2]
=5!/(2!(52)!
=10
Probability of choosing both
= 1 / 10