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Prime number

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Prime number

by chidcguy » Thu Jun 26, 2008 10:52 am
If N is a prime number greater than 3, what is the remainder when N is divided by 12?

(A) 0

(B) 1

(C) 2

(D) 3

(E) 5
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by Carol » Thu Jun 26, 2008 11:55 am
when a smaller integer is divided by a larger integer, the quotient is 0

so, I picked 5 as a prime number bigger than 3 and

using the following formula:

n = xq + r

plugging the numbers into it:

5=12 x 0 + r ---> remainder 5


am I correct?
Last edited by Carol on Thu Jun 26, 2008 2:25 pm, edited 1 time in total.
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by chidcguy » Thu Jun 26, 2008 1:03 pm
How about If Pick 7 and some one else picks 11 or 13
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by egybs » Thu Jun 26, 2008 1:13 pm
where's this question from?

As stated, I don't think it makes sense.
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by Ian Stewart » Thu Jun 26, 2008 1:14 pm
Clearly both 1 and 5 are possible remainders, as are 7 and 11. There's something wrong with the question. What's the source?
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by Carol » Thu Jun 26, 2008 1:29 pm
but the possible answers are: 0, 1,2,3,5.

so I picked 5 because they asked you for a prime number greater than 3, hence 5, right?


what's the OA ?
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by chidcguy » Thu Jun 26, 2008 1:50 pm
This is from a GMAT paper test. Answer is B. Did not make any sense to me and thats why I posted here to see if I was trapped.
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by Carol » Thu Jun 26, 2008 2:21 pm
I would have faild as well...

according to the OA, I think:

the numerator must be greater than the dominator, for the quotient won't be zero!

again the formula:

n = xq + r

I chose 13 as the prime number greater than 3

and

13 = 12 x 1 + 1

I think this sounds correct this time. I think the question missed smth, they should have given us more data.

What do you think?
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by Ian Stewart » Thu Jun 26, 2008 3:39 pm
Carol wrote: the numerator must be greater than the dominator, for the quotient won't be zero!
There's nothing wrong with having a quotient of zero in this question. All we know is that N is greater than 3. Unless some information is missing from the question itself, or something has been mistranscribed, there isn't enough information here to give a unique answer- there are four possible answers (1, 5, 7, 11). If you replace the number '12' in the question with a '2', however, then the answer would be B, since you'd know N was odd. That's the only quick adjustment I can think to make to the question if we want the question to make any sense.
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by mttorii » Thu Jun 26, 2008 4:20 pm
Carol,

Using your formula, It also works with 17 (prime number)
17 = 12 x 1 + 5 ... and therefore we have a different reminder.

Furthermore
25 = 12 x 2 + 1

So B should not be the answer because 25 is not a prime number.
Anyway this question sounds strange.
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