Multiple choice

20 cards are numbered from 1 to 20. If one card is drawn at random, what is the probability that the number on the card is a prime number?

  1. 1/ 5

  2. 2/ 5

  3. 3/ 5

  4. 4 / 5
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B Correct answer
Explanation

The prime numbers between 1 and 20 are 2, 3, 5, 7, 11, 13, 17, 19. There are 8 such numbers. The probability is 8/20, which simplifies to 2/5.

AI explanation

Using the classical definition of probability, the probability equals the number of prime numbers divided by the total number of outcomes. The prime numbers between 1 and 20 are 2, 3, 5, 7, 11, 13, 17 and 19, giving 8 favorable outcomes out of 20 possible cards. Therefore, the probability is 8/20, which simplifies to 2/5.

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