What is the probability of rolling a prime number of a standard 20-sided die? (1 is not a prime number.)

The prime numbers from 1 through 20 are 2, 3, 5, 7, 11, 13, 17, and 19, so there are 8 prime outcomes. A 20-sided die has 20 equally likely outcomes, giving a probability of 8/20 = 2/5. The correct choice is 2/5.

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