Probability
Classical Probability
Grade 12

Question:

<p><b>For Problems 6 and 7:</b> A box \(B_1\) contains 1 white ball, 3 red balls, and 2 black balls. Another box \(B_2\) contains 2 white balls, 3 red balls, and 4 black balls. A third box \(B_3\) contains 3 white balls, 4 red balls, and 5 black balls.</p><p><b>Problem 6:</b> If 1 ball is drawn from each of the boxes \(B_1\), \(B_2\) and \(B_3\), the probability that all 3 drawn balls are of the same color is</p>
<p>82/648</p>
<p>90/648</p>
<p>558/648</p>
<p>566/648</p>

Step-by-Step Solution

Key Concept: When drawing from multiple independent boxes, find the probability for each color separately (all white OR all red OR all black), then sum these mutually exclusive events.
**Step 1: Count balls in each box** The contents of each box are: * Box $B_1$: 1 white ball, 3 red balls, 2 black balls. Total balls: $1+3+2=6$. * Box $B_2$: 2 white balls, 3 red balls, 4 black balls. Total balls: $2+3+4=9$. * Box $B_3$: 3 white balls, 4 red balls, 5 black balls. Total balls: $3+4+5=12$. **Step 2: Calculate the probability that all 3 drawn balls are white** The probability of drawing a white ball from each box is: $$P(\text{all White}) = P(W_1) \times P(W_2) \times P(W_3) = \frac{1}{6} \times \frac{2}{9} \times \frac{3}{12} = \frac{6}{648}$$ **Step 3: Calculate the probability that all 3 drawn balls are red** The probability of drawing a red ball from each box is: $$P(\text{all Red}) = P(R_1) \times P(R_2) \times P(R_3) = \frac{3}{6} \times \frac{3}{9} \times \frac{4}{12} = \frac{36}{648}$$ **Step 4: Calculate the probability that all 3 drawn balls are black** The probability of drawing a black ball from each box is: $$P(\text{all Black}) = P(B_1) \times P(B_2) \times P(B_3) = \frac{2}{6} \times \frac{4}{9} \times \frac{5}{12} = \frac{40}{648}$$ **Step 5: Calculate the total probability that all 3 drawn balls are of the same color** The events of drawing all white, all red, or all black balls are mutually exclusive. Therefore, the total probability that all 3 drawn balls are of the same color is the sum of their individual probabilities: $$P(\text{same color}) = P(\text{all White}) + P(\text{all Red}) + P(\text{all Black})$$ $$P(\text{same color}) = \frac{6}{648} + \frac{36}{648} + \frac{40}{648}$$ $$P(\text{same color}) = \frac{6 + 36 + 40}{648} = \frac{82}{648}$$
Correct Answer: B

Master Probability with Mathbee

Practice this topic under real exam conditions with strict timers, or ask our AI Mentor to explain the concepts step-by-step.

Start Practicing for Free