Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Re: Math DS (m05q29) [#permalink]
25 Oct 2009, 09:45

eyunni wrote:

Is 4Q/11 a positive integer?

(1) Q is a prime number (2) 2Q is divisible by 11

1: Q could be 2 or 3 or 5 or 7 or 11 or 13. NSF.. 2: Q could be -ve, 0 or +ve. For ex: -11 or -5.50 or 0 or 5.50 or 11 or any multiples of 11. NSF..

1&2: Q must be a prime and 2Q must be divisible by 11.

Q must be a prime eliminates the chances that Q is a -ve, 0 and fraction. Given that Q is a prime and 2Q must be divisible by 11 eliminate the chances that Q is other than 11.

Therefore Q = 11 and 4Q/11 is a +ve integer i.e. 4.

Re: Math DS (m05q29) [#permalink]
26 Jun 2010, 17:12

C

1) Q can be 11 => it works or Q can be 3 => is not good, hence insufficient 2) 2Q is divisible by B, but we don't know if the result of this division is a positive integer, hence insufficient

(1) q is a prime number --> if q=2 then the answer is NO but if q=11 then the answer is YES. Not sufficient.

(2) 2q is divisible by 11 --> \frac{2q}{11}=integer --> 2*\frac{2q}{11}=\frac{4q}{11}=2*integer=integer, but we don't know whether this integer is positive or not: consider q=0 and q=11. Not sufficient.

(1)+(2) Since q is a prime number and 2q is divisible by 11, then q must be equal to 11 (no other prime but 11 will yield integer result for \frac{2q}{11} ) --> \frac{4q}{11}=4. Sufficient.