Question

Two numbers are selected randomly from the set S = {1, 2, 3, 4, 5, 6} 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

Answer 1

Answer: (D)

4/5

Answer 2

Total choices = .

Favourable cases: If first number is either of 1, 2 and 3, then second number can be any number = .

But if first number is either of 4, 5 and 6, then second number is either of 1, 2 and 3 = $\left( { } ^ { 3 } \mathrm { C } _ { 1 } \right) ^ { 2 }$ .

So, total favourable cases = .

∴ Probability = $\frac { 24 } { 30 } = \frac { 4 } { 5 }$ .