If p is a positive integer, is integer k prime?

Question

(1) 3p + 3 = k
(2) 7! + 3 = k

broall · Answer

(1) $k=3(p+1)$. Hence $k$ is divisible by 3 and $p+1 \implies k$ is not a prime. Sufficient.

(2) We have the specific value of $k$, doesn't matter what value of $k$ is. Sufficient.

In fact, $k=7!+3$ is divisible by 3 so $k$ is not a prime.

The answer is D.

Abhishek009 · Answer

FROM STATEMENT - I   ( SUFFICIENT )

3p + 3 = k

Or, 3 ( p + 1 ) = k

So, k is divisible by 3 ; hence k can not be a prime number...

FROM STATEMENT - II   ( SUFFICIENT )

7! + 3 = k

Or, 7*6*5*4*3*2*1 + 3 = k

Or, 3 ( 7*6*5*4*2*1 + 1 ) = k

So, k is divisible by 3 ; hence k can not be a prime number...
  
Thus, EACH statement ALONE is sufficient to answer the question asked, aswer will be (D)

hyppo0 · Answer

Hi all,
statement 1
If p=0, then k=3 -> so K prime! Am I missing something?

amanvermagmat · Answer

Hi

Its given that p is a positive integer, so we cannot take the case where p=0.

rashwiniyer · Answer

I thought zero is both positive and negative.

LeoN88 · Answer

#1 k= 3(P+1), so k can't be prime as it's definitely divided by 3.

#2 k= 3(1+x), where x>0 and Integer, so again k can't be prime as it's definitely divided by 3..

D  Each statement independently sufficient.

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LeoN88 · Answer

rashwiniyer

zero is neither +ve nor -ve.

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ILMENF · Answer

For statement 1, stating that if it is divisible by 3, then it is not prime I believe it is wrong: 3 is prime and is divisible by 3. The correct statement would be that for every value of x, the result won't be prime.

If p is a positive integer, is integer k prime?

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GMAT Data Sufficiency (DS) Questions

If p is a positive integer, is integer k prime?

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