[Math Revolution GMAT math practice question]
If n is an integer greater than 1, what is the value of n?
1) n is a prime number
2) (n+2)/n is an integer
If n is an integer greater than 1, what is the value of n?
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- Max@Math Revolution
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Statement 1:Max@Math Revolution wrote:[Math Revolution GMAT math practice question]
If n is an integer greater than 1, what is the value of n?
1) n is a prime number
2) (n+2)/n is an integer
Here, n can be any prime number.
INSUFFICIENT.
Statement 2:
(n+2)/n = n/n + 2/n = 1 + 2/n.
Given that n must be an integer, 1 + 2/n will yield an integer value only if n is a FACTOR OF 2.
Factors of 2: 1 and 2.
Since n must be greater than 1, n=2.
SUFFICIENT.
The correct answer is B.
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- Max@Math Revolution
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=>
Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.
Since we have 1 variable (n) and 0 equations, D is most likely to be the answer. So, we should consider each of the conditions on their own first.
Condition 1)
Since there are many prime numbers, condition 1) is not sufficient.
Condition 2)
If n = 1, then (n+2)/n = 3 is an integer.
If n = 2, then (n+2)/n = 2 is an integer.
Since we don't have a unique solution, condition 2) is not sufficient.
Conditions 1) & 2)
If n = 2, then (n+2)/n = 2 is an integer.
If n = 3, then (n+2)/n = 5/2 is not integer.
If n is a prime number bigger than 2, (n+2)/n is not an integer.
Thus n = 2 is the unique solution and both conditions together are sufficient.
Therefore, C is the answer.
Answer: C
If the original condition includes "1 variable", or "2 variables and 1 equation", or "3 variables and 2 equations" etc., one more equation is required to answer the question. If each of conditions 1) and 2) provide an additional equation, there is a 59% chance that D is the answer, a 38% chance that A or B is the answer, and a 3% chance that the answer is C or E. Thus, answer D (conditions 1) and 2), when applied separately, are sufficient to answer the question) is most likely, but there may be cases where the answer is A,B,C or E.
Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.
Since we have 1 variable (n) and 0 equations, D is most likely to be the answer. So, we should consider each of the conditions on their own first.
Condition 1)
Since there are many prime numbers, condition 1) is not sufficient.
Condition 2)
If n = 1, then (n+2)/n = 3 is an integer.
If n = 2, then (n+2)/n = 2 is an integer.
Since we don't have a unique solution, condition 2) is not sufficient.
Conditions 1) & 2)
If n = 2, then (n+2)/n = 2 is an integer.
If n = 3, then (n+2)/n = 5/2 is not integer.
If n is a prime number bigger than 2, (n+2)/n is not an integer.
Thus n = 2 is the unique solution and both conditions together are sufficient.
Therefore, C is the answer.
Answer: C
If the original condition includes "1 variable", or "2 variables and 1 equation", or "3 variables and 2 equations" etc., one more equation is required to answer the question. If each of conditions 1) and 2) provide an additional equation, there is a 59% chance that D is the answer, a 38% chance that A or B is the answer, and a 3% chance that the answer is C or E. Thus, answer D (conditions 1) and 2), when applied separately, are sufficient to answer the question) is most likely, but there may be cases where the answer is A,B,C or E.
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- GMATGuruNY
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Since the prompt indicates that n is an integer greater than 1, the case in red is not possible.Max@Math Revolution wrote:Condition 2)If n is an integer greater than 1, what is the value of n?
1) n is a prime number
2) (n+2)/n is an integer
If n = 1, then (n+2)/n = 3 is an integer.
If n = 2, then (n+2)/n = 2 is an integer.
Since we don't have a unique solution, condition 2) is not sufficient.
Conditions 1) & 2)
If n = 2, then (n+2)/n = 2 is an integer.
If n = 3, then (n+2)/n = 5/2 is not integer.
If n is a prime number bigger than 2, (n+2)/n is not an integer.
Thus n = 2 is the unique solution and both conditions together are sufficient.
Therefore, C is the answer.
Answer: C
The only value that satisfies Statement 2 is n=2, making Statement 2 SUFFICIENT.
The correct answer thus is not C but B.
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Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
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