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An integer is randomly chosen from 2 to 20 inclusive. What i
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05 Aug 2018, 14:23
05 Aug 2018, 14:23
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An integer is randomly chosen from 2 to 20 inclusive. What is the probability that the number is prime?
Give your answer as a fraction.
Give your answer as a fraction.
Show: :: OA
\(\frac{8}{19}\)
Re: An integer is randomly chosen from 2 to 20 inclusive. What i
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07 Aug 2018, 06:05
07 Aug 2018, 06:05
Expert Reply
Explanation
Among the integers 2 through 20, inclusive, there are 8 primes: 2, 3, 5, 7, 11, 13, 17, and 19. From 2 to 20, inclusive, there are exactly 20 – 2 + 1 = 19 integers; remember to “add one before you’re done” to include both endpoints.
Alternatively, there are 20 integers from 1 to 20, inclusive, so there must be 19 integers from 2 to 20, inclusive. Since probability is defined as the number of desired items divided by the total number of choices, the probability that the number chosen is prime is \(\frac{8}{19}\).
Among the integers 2 through 20, inclusive, there are 8 primes: 2, 3, 5, 7, 11, 13, 17, and 19. From 2 to 20, inclusive, there are exactly 20 – 2 + 1 = 19 integers; remember to “add one before you’re done” to include both endpoints.
Alternatively, there are 20 integers from 1 to 20, inclusive, so there must be 19 integers from 2 to 20, inclusive. Since probability is defined as the number of desired items divided by the total number of choices, the probability that the number chosen is prime is \(\frac{8}{19}\).
gmatclubot
Re: An integer is randomly chosen from 2 to 20 inclusive. What i [#permalink]
07 Aug 2018, 06:05
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