Author 
Message 
TAGS:


Intern
Joined: 24 May 2016
Posts: 33
Followers: 0
Kudos [?]:
7
[0], given: 22

Question Stats:
47% (00:45) correct
52% (01:01) wrong based on 17 sessions
10! is divisible by \(3^x5^y\), where x and y are positive integers
Quantity A 
Quantity B 
The greatest possible value for x 
The greatest possible value for y 
A) Quantity A is greater. B) Quantity B is greater. C) The two quantities are equal. D) The relationship cannot be determined from the information given.
Last edited by Carcass on 26 Mar 2018, 09:28, edited 3 times in total.
Edited by Carcass




Manager
Joined: 15 Jan 2018
Posts: 147
GMAT 1: Q V
Followers: 3
Kudos [?]:
173
[2]
, given: 0

Re: Quantitative Reasoning [#permalink]
14 Mar 2018, 23:58
2
This post received KUDOS
10! means 10x9x8x7x6x5x4x3x2x1. Just getting that out of the way. So if we want to know the maximum value of x, we basically need to count up how many 3s there are in 10!. Every third integer is divisible by 3, so that's 3, 6, and 9. It's a trap to think you're done here. We should also realize that every ninth integer is divisible by 9, and 9 has two 3s as factors. In other words, 9 should count twice. So x = 4, not 3. Using similar logic, we know that 5 and 10 have factors of 5, so y must be 2. Thus, the answer is A.
_________________
    
Need help with GRE math? Check out our groundbreaking books and app.
Last edited by SherpaPrep on 03 Apr 2018, 09:48, edited 1 time in total.



Moderator
Joined: 18 Apr 2015
Posts: 4917
Followers: 74
Kudos [?]:
980
[1]
, given: 4510

Re: Quantitative Reasoning [#permalink]
15 Mar 2018, 01:34
1
This post received KUDOS
Dear away, Following the rules is not easy but also is fundamental because for the other students is a straight forward way to find a question. Posting images do not help at all. See this post how to post a question is a few and really simple steps. https://greprepclub.com/forum/qqhowto ... 2357.htmlHowever, I summarize for you what to do: post a question on the right forum for instance a numeric entry on the relative subforum, the title of the question should be the first sentence of the question for an easy search, with a comparison question use the tag quantity to set up the two in the proper manner, use the tags to identify the question as level of difficulty type and source. It seems a lot of work but it is just 20 seconds. @update look now how it appears I edited the question Regards
_________________
Get the 2 FREE GREPrepclub Tests



Manager
Joined: 27 Sep 2017
Posts: 112
Followers: 1
Kudos [?]:
29
[0], given: 4

Re: Quantitative Reasoning [#permalink]
15 Mar 2018, 07:11
SherpaPrep wrote: 10! means 10x9x8x7x6x5x4x3x2x1. Just getting that out of the way. So if we want to know the maximum value of x, we basically need to count up how many 3s there are in 10!. Every third integer is divisible by 3, so that's 3, 6, and 9. It's a trap to think you're done here. We should also realize that every ninth integer is divisible by 9, and 9 has two 3s as factors. In other words, 9 should count twice. So x = 4, not 3.
Using similar logic, we know that 5 and 10 have factors of 5, so y must be 2. Thus, 2y = 4 and the answer is C. Are u really sure ANS is C, I don't see "2y", where is it from?



Manager
Joined: 22 Feb 2018
Posts: 90
Followers: 2
Kudos [?]:
65
[2]
, given: 9

Re: 10! is divisible [#permalink]
15 Mar 2018, 15:58
2
This post received KUDOS
correct: A we should write the number 10! into it's simplest form consisting of just prime numbers. 10! = 10 * 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1 = \(2^8 *3^4 * 5^2 * 7\) 10! = \(3^x * 5^y\) so x = 4 and y = 2 so x is bigger than y
Last edited by Carcass on 16 Mar 2018, 02:20, edited 1 time in total.
Edited by Carcass



Manager
Joined: 15 Feb 2018
Posts: 53
Followers: 1
Kudos [?]:
17
[0], given: 33

Re: 10! is divisible [#permalink]
16 Mar 2018, 03:40
How is the answer C? I am getting A. I have x = 4 and y = 2.



Manager
Joined: 26 Jun 2017
Posts: 104
Followers: 0
Kudos [?]:
38
[1]
, given: 38

Re: 10! is divisible [#permalink]
21 Mar 2018, 16:12
1
This post received KUDOS
The sad part of story is that I spent 10 minutes from my valuable time trying to prove me wrong while I was right
_________________
What you think, you become.



Intern
Joined: 11 Jan 2018
Posts: 44
Followers: 0
Kudos [?]:
26
[0], given: 7

Re: 10! is divisible [#permalink]
26 Mar 2018, 09:24
Please correct the OA of this question. Choice A is correct.
_________________
Persistence >>>>>>> Success
Don't say thanks, just give KUDOS. 1 kudos = 1000 Thanks



Moderator
Joined: 18 Apr 2015
Posts: 4917
Followers: 74
Kudos [?]:
980
[1]
, given: 4510

Re: 10! is divisible [#permalink]
26 Mar 2018, 09:29
1
This post received KUDOS
Done. Thank you guys for your collaboration. However, next time posts like this one will be closed. Regards
_________________
Get the 2 FREE GREPrepclub Tests




Re: 10! is divisible
[#permalink]
26 Mar 2018, 09:29





