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Set S is the set of all prime integers between 0 and 20. If
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20 Dec 2019, 06:05
20 Dec 2019, 06:05
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Set S is the set of all prime integers between 0 and 20. If three numbers are chosen randomly from set S and each number can be chosen only once, what is the positive difference between the probability that the product of these three numbers is a number less than 31 and the probability that the sum of these three numbers is odd?
A. \(\frac{1}{336}\)
B. \(\frac{1}{2}\)
C. \(\frac{17}{28}\)
D. \(\frac{3}{4}\)
E. \(\frac{301}{336}\)
Kudos for the right answer and explanation
A. \(\frac{1}{336}\)
B. \(\frac{1}{2}\)
C. \(\frac{17}{28}\)
D. \(\frac{3}{4}\)
E. \(\frac{301}{336}\)
Kudos for the right answer and explanation
Re: Set S is the set of all prime integers between 0 and 20. If
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22 Dec 2019, 05:40
22 Dec 2019, 05:40
5
Primes within range: 2,3,5,7,11,13,17,19 - 8
Total selection = 8C3 = 56
Probablity_case_1:
add two odds to get a even , obviously to get odd we need to keep 2 out of the sum
Total even sums = Total selection of 3 numbers in 3,5,7,11,13,17,19 (all except 2) = 7C3 = 35
Probablity_case_2:
Multiplication of 3 must be less than 31 (ofcourse 2*3*5 = 30)
Anything more than 5 beyond range os there is just one instance
P1-P2 = 35/56 - 1/56 = 17/28
Total selection = 8C3 = 56
Probablity_case_1:
add two odds to get a even , obviously to get odd we need to keep 2 out of the sum
Total even sums = Total selection of 3 numbers in 3,5,7,11,13,17,19 (all except 2) = 7C3 = 35
Probablity_case_2:
Multiplication of 3 must be less than 31 (ofcourse 2*3*5 = 30)
Anything more than 5 beyond range os there is just one instance
P1-P2 = 35/56 - 1/56 = 17/28
General Discussion
Re: Set S is the set of all prime integers between 0 and 20. If
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06 Dec 2021, 00:36
06 Dec 2021, 00:36
Hello from the GRE Prep Club BumpBot!
Thanks to another GRE Prep Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).
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Thanks to another GRE Prep Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).
Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
