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Author:  GMATBusters [ 06 Dec 2018, 05:36 ] 
Post subject:  If n is a positive integer, are n and 1 the only positive divisors of 
If n is a positive integer, are n and 1 the only positive divisors of n? (1) n is less than 14. (2) If n is doubled, the result is less than 27 
Author:  Chethan92 [ 06 Dec 2018, 19:02 ] 
Post subject:  Re: If n is a positive integer, are n and 1 the only positive divisors of 
Question : Whether n and 1 are the only positive divisors of n? Question is asking whether n is prime or not. From statement 1: n < 14 If n is 2, then 2 and 1 are the only divisors of 2. If n is 4, then 1,2 and 4 are the divisors of 4. Hence, Insufficient. From statement 2: If n = 2n, then 2n < 27. Still Insufficient. Combining both: Again n can be a prime or a nonprime number. Insufficient. E is the answer. 
Author:  BrentGMATPrepNow [ 25 Mar 2020, 05:45 ] 
Post subject:  Re: If n is a positive integer, are n and 1 the only positive divisors of 
GMATBusters wrote: If n is a positive integer, are n and 1 the only positive divisors of n? (1) n is less than 14. (2) If n is doubled, the result is less than 27 Target question: Are n and 1 the only positive divisors of n? This is a good candidate for rephrasing the target question. If n and 1 the only positive divisors of n, what does this tell us about n? It tells us that n is prime (since prime numbers are the only numbers with exactly 2 divisors) So the original target question is really just asking us to determine whether n is prime... REPHRASED target question: Is n prime? Aside: the video below has tips on rephrasing the target question Statement 1: n is less than 14 There are several values of n that satisfy statement 1. Here are two: Case a: n = 2. In this case, the answer to the REPHRASED target question is YES, n is prime Case b: n = 6. In this case, the answer to the REPHRASED target question is NO, n is not prime Since we cannot answer the REPHRASED target question with certainty, statement 1 is NOT SUFFICIENT Statement 2: If n is doubled, the result is less than 27 This information feels just as vague as the information provided him statement 1. So, perhaps I'll test some numbers here. IMPORTANT: If you're going to test some values, you can sometimes save time by first checking to see whether we can reuse the values you used when analyzing statement 1. In this case, both values (n = 2 and n = 6) also satisfy statements 2. That is: Case a: n = 2. In this case, the answer to the REPHRASED target question is YES, n is prime Case b: n = 6. In this case, the answer to the REPHRASED target question is NO, n is not prime Since we cannot answer the REPHRASED target question with certainty, statement 2 is NOT SUFFICIENT Statements 1 and 2 combined Since I was able to use the same counterexamples to show that each statement ALONE is not sufficient. So, the same counterexamples will satisfy the two statements COMBINED. In other words, Case a: n = 2. In this case, the answer to the REPHRASED target question is YES, n is prime Case b: n = 6. In this case, the answer to the REPHRASED target question is NO, n is not prime Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT Answer: E Cheers, Brent RELATED VIDEO 
Author:  dadie [ 27 Jul 2020, 13:35 ] 
Post subject:  Re: If n is a positive integer, are n and 1 the only positive divisors of 
Is n a prime number ? 1 prime umber less than 14 9 they are moe than one (2, 3, 5, 7 etc...) Not Sufficient 2 2n< 27, a lot of number are in this case 3 both 2*2, 3*2 and 7*2 are less than 27 so the answer is E 
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Post subject:  Re: If n is a positive integer, are n and 1 the only positive divisors of 
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