Multiple choice

There are $7$ defective bulbs and $20$ undefective bulbs in a bag. A bulb is selected from the bag. Find the probability that it is undefective.

  1. $\dfrac{7}{27}$
  2. $\dfrac{20}{27}$
  3. $\dfrac{1}{27}$
  4. $\dfrac{7}{20}$
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B Correct answer
Explanation

Total bulbs = 7 + 20 = 27. Number of undefective bulbs = 20. Probability = 20 / 27.

AI explanation

By the classical definition of probability, the likelihood of an event is the ratio of favorable outcomes to total outcomes. The total number of bulbs is 27 (20 undefective plus 7 defective). The probability of selecting an undefective bulb is therefore 20 divided by 27.

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