CA Foundation · Quantitative Aptitude · Probability
If A and B are independent events with P(A) = 0.4 and P(B) = 0.5, what is the probability that both A and B occur?
The probability that both events occur is 0.20. For independent events the multiplication theorem says P(A and B) equals P(A) times P(B), so 0.4 multiplied by 0.5 gives 0.20. Adding the probabilities would be incorrect for a joint occurrence.
- A0.9
- B0.20Correct
- C0.10
- D0.45
Explanation
For independent events, P(A and B) = P(A) × P(B) = 0.4 × 0.5 = 0.20. The value 0.9 is the simple sum of the probabilities, which wrongly adds instead of multiplying.
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