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Prime factorization

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by immaculatesahai » Sat Dec 10, 2011 1:02 am
I thought this was straight forward.

(13!12!)+(13!14!)

13!(12!+14!)

13!12!183

61 IS the biggest prime number that divides 183. 61 is the solution.
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by gunjan1208 » Sat Dec 10, 2011 1:56 am
I loved this question since it gives the example what a simple question can become....if not handled properly, its hell of a vertical height mapping.

Thank you Dana J
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by mourinhogmat1 » Tue Jan 03, 2012 6:51 pm
Fantastic question! Fell for 13. But realized we need to expand/factorize such questions before we conclude.
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by ronnie1985 » Fri Feb 03, 2012 8:11 am
factoring give 183*(12!)*(13!)
Factor = 61
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by bhanu marwaha » Sat Feb 18, 2012 12:50 am
13!*12!(1+14*13)
13!*12!(183)
13!*12!(3*61)

in 13!*12! you cannot have a number which will be prime and greater than 61 )
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by ronnie1985 » Sat Feb 18, 2012 7:40 am
(D) QED
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by Ganesh hatwar » Thu Aug 02, 2012 1:13 am
DanaJ wrote:Source: Veritas Prep

What is the greatest prime factor of (13!12!) + (13!14!)?

A. 11
B. 13
C. 47
D. 61
E. 71

Hehe, really liked this one! Let's see if you can nail it! :)
B??? Just guess taking 13 common
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by chris558 » Wed Aug 08, 2012 6:48 am
D) 61

(13!12!)+(13!14!)...
Factor out common factors which in this case would be 13! and 12!
13!12!(1+(13)(14))
We know that 13!12! is not prime, so now calculate what is inside the parentheses...
1+(13)(14)=182+1=183=3(61)
61 is prime. Answe ris D.
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by surmilsehgal » Sun Aug 12, 2012 8:25 am
Answer is D
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by djc225 » Sun Sep 02, 2012 5:35 am
what's the quickest way to determine that 61 is the greatest prime factor of 183? i understand that I can check if it's divisible by 3 and then come to 61, but how would i konw that it's the greatest prime factor? (i'm looking at this from a DS point of view where i cant just rule out choices from the answers)
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by adthedaddy » Sun Sep 02, 2012 9:22 am
Dear djc225,

If you factorize 183, then it has only two factors -> 3 and 61.
Thats it... 61 is prime and greatest... hence it is the greatest prime factor...

Note: The other terms are 13! and 12!
We know that the greatest prime factor of 13! is 13 and for 12! its 11.
So left is only 183 which 3*61...
Thus 61 is the greatest prime factor
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by mparakala » Mon Dec 10, 2012 7:33 pm
13!12!(1+14*13) = 13!12!(183)
61 is the greatest prime factor of 183. hence, the same for the complete ans

D
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by Kshitij Sharma » Wed Dec 26, 2012 1:15 am
61 is the largest prime factor for this problem.

13!12!(1+14x13) = 13!12!(183) = 13!12!(3x61)
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by ritzzzr » Thu Feb 14, 2013 3:52 am
61 IS THE ANSWER!!
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by rajeshsinghgmat » Sun Feb 17, 2013 2:39 am
D in answer.

(13!12!) + (13!14!)

=(13)(12!)(12!) + (13)(12!)(14)(13)(12!)

=(13)(12!)(12!)(1+13*14)

=(13)(12!)(12!)(183)

=(13)(12!)(12!)(3)(61)
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