Bunuel wrote:
Is the tens digit of a two digit integer k divisible by 3?(1) k-5 is a multiple of 3 --> \(k-5=3m\) --> \(k=3m+5=3(m+1)+2\). So, we have that \(k\) is 2 more than a multiple of 3. Now, if \(k=11\) (2 more than 9), then the answer is NO, but if \(k=32\) (2 more than 30), then the answer is YES. Not sufficient.
(2) k-11 is a multiple of 3 --> \(k-11=3n\) --> \(k=3n+11=3(n+3)+2\). The same info as above: \(k\) is 2 more than a multiple of 3. Not sufficient.
(1)+(2) Nothing new. Not sufficient.
Answer: E.
P.S. Please provide OA's for the questions you post. Rule #7 here: rules-for-posting-please-read-this-before-posting-133935.html If you don't have OA you must indicate that in the post. Hi, Bunuel
If I understood correctly both functions leave remainder of 2 and that'swhy you understood that combination wouldn't add anything new.
(by the way in your explanation you named 3m+5 and the other 3n+11, why don't we name them both n or m, is it because when we name it that way we get equation like 0=6 ?)But what if 2nd statement was k+10 or k+7 , which would be K=3*(m+1)+1 and , how would you solve that one and know combination of both statements wouldn't provide answer.
B) on the GMAT how you can determine whether it is better to use function as you always do or put number. Of course you provide detailed answer , but I think here it could be more efficient to use number. Want to know your opinion
Thank You
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Press +1 Kudos if my post helped you a little and help me to ulcock the tests Wish you all success