CMA Foundation · Fundamentals of Business Mathematics and Statistics · Probability
In a Chennai firm, 60% of employees know Excel, 40% know Tally and 25% know both. If an employee is chosen at random, what is the probability that the employee knows neither Excel nor Tally?
The probability that the employee knows neither skill is 0.25. Using the addition rule, the chance of knowing at least one is 0.60 plus 0.40 minus 0.25, which is 0.75, and subtracting from 1 leaves 0.25.
- A0.15Correct
- B0.25
- C0.35
- D0.05
Explanation
P(E or T) = 0.60 + 0.40 - 0.25 = 0.75. P(neither) = 1 - 0.75 = 0.25. Hence the correct value is 0.25. Option 0.15 comes from wrongly treating the union as 0.85.
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