Question

A bag contains 3 red, 6 white and 7 blue balls. What is the probability that 2 balls drawn are white and blue?

• A. 1/120
• B. 1/16
• C. 13/16
• D. 7/20

Hint:

When drawing balls simultaneously, use Combinations ($nCr$) for accuracy.

Answer 1

The Correct Option is D

Step 1: Concept
Probability = (Favorable Outcomes) (Total Outcomes).

Step 2: Total Outcomes
Total balls = $3 + 6 + 7 = 16$. Ways to draw 2 balls = ${}^{16}C_2 = \frac{16 \times 15}{2} = 120$.

Step 3: Favorable Outcomes
Ways to draw 1 white ball AND 1 blue ball = ${}^6C_1 \times {}^7C_1 = 6 \times 7 = 42$.

Step 4: Conclusion
Probability = $42 / 120$. Reducing by 6: $7 / 20$. Final Answer: (D)