Another Factor problem..

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Source: — Data Sufficiency |

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by arora007 » Sat Aug 07, 2010 9:11 am
errata Idiom test 14/52 answer choice smolke instead of smoke

choice 1
4! = 4*3*2=24
assume k=25 then we have a p=5

assume k=29 then we do not have a factor of this prime number between 29 and 1.
INSUFFICIENT

13!+2 <= k <= 13!+13

k could take values

1*2*....13 +2 = 2 *((3*4*...13) +1)
or
1*2*....13 +3 = 3 *((2*4*...13) +1)
and so on...
upto
1*2*....13 +13 = 13 *((2*3*...12) +1)

k is a multiple of anything between 2 and 13
ans B


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by KrazyKarl » Sat Aug 07, 2010 6:34 pm
I knew I remembered seeing a problem really similar to this in the last week or so on here:

https://www.beatthegmat.com/prime-number ... tml#279183

I guess that's why it pays to study: since I had seen something so similar in the last week and read all the explanation, this one wasn't too hard for me! Now if I can only master the other 10,000 question varieties I should score over 700 no problem!