Two numbers are selected randomly from the set without replacement one by one. The probability that minimum of the two numbers is less than 4, is
- A.1/15
- B.14/15
- C.1/5
- D.4/5
Show answer and solution
Correct option: D
Solution
The complement is that the minimum of the two numbers is ≥ 4, meaning both numbers are from {4, 5, 6}. The number of ways to choose 2 from {4, 5, 6} is C(3,2) = 3, and total ways to choose 2 from 6 is C(6,2) = 15. So P(min ≥ 4) = 3/15 = 1/5, and P(min < 4) = 1 - 1/5 = 4/5.
[AIEEE 2003]