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A “trio-prime” is any number made up of three factors, not
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22 Oct 2017, 06:16
22 Oct 2017, 06:16
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43% (01:06) wrong based on 23 sessions
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A “trio-prime” is any number made up of three factors, not including itself and 1, that are consecutive primes. How many “trio-primes” are less than 1,000?
(A) 2
(B) 3
(C) 4
(D) 7
(E) 11
Kudos for correct solution.
(A) 2
(B) 3
(C) 4
(D) 7
(E) 11
Kudos for correct solution.
Re: A “trio-prime” is any number made up of three factors, not
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22 Oct 2017, 09:21
22 Oct 2017, 09:21
2
We can start listing the triplets of consecutive prime numbers we need to analyze, i.e. 2*3*5, 3*5*7, 5*7*11, 7*11*13, ... We should start from the highest in order to have an idea of where we are with respect to 1000. 7*11*13 = 1001, thus we know that the triplets before are those of interest, i.e. 2*3*5, 3*5*7 and 5*7*11. Thus, answer is 3 (B)
Re: A “trio-prime” is any number made up of three factors, not
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11 May 2018, 07:06
11 May 2018, 07:06
IlCreatore wrote:
We can start listing the triplets of consecutive prime numbers we need to analyze, i.e. 2*3*5, 3*5*7, 5*7*11, 7*11*13, ... We should start from the highest in order to have an idea of where we are with respect to 1000. 7*11*13 = 1001, thus we know that the triplets before are those of interest, i.e. 2*3*5, 3*5*7 and 5*7*11. Thus, answer is 3 (B)
how can we be sure that there are no other TRIO PRIME no others other than 3?
