CA Foundation · Quantitative Aptitude · Probability
A fair coin is tossed and a fair die is rolled together. What is the probability of getting a head and a number greater than 4 on the die?
The probability is 1/6. The coin toss and die roll are independent, so multiply P(head) = 1/2 by P(5 or 6) = 1/3, giving 1/6. Option 1/3 ignores the coin altogether.
- A1/6Correct
- B1/2
- C1/3
- D2/3
Explanation
The two experiments are independent. P(head) = 1/2 and P(number greater than 4) = 2/6 = 1/3. The product is 1/2 x 1/3 = 1/6. Option 1/3 is just the die probability, missing the head factor.
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