GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 18 Feb 2019, 14:45

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

## Events & Promotions

###### Events & Promotions in February
PrevNext
SuMoTuWeThFrSa
272829303112
3456789
10111213141516
17181920212223
242526272812
Open Detailed Calendar
• ### Valentine's day SALE is on! 25% off.

February 18, 2019

February 18, 2019

10:00 PM PST

11:00 PM PST

We don’t care what your relationship status this year - we love you just the way you are. AND we want you to crush the GMAT!
• ### Get FREE Daily Quiz for 2 months

February 18, 2019

February 18, 2019

10:00 PM PST

11:00 PM PST

Buy "All-In-One Standard ($149)", get free Daily quiz (2 mon). Coupon code : SPECIAL # Let n~ be defined for all positive integers n as the remainder when (n  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics Author Message TAGS: ### Hide Tags Senior Manager Joined: 12 Aug 2015 Posts: 283 Concentration: General Management, Operations GMAT 1: 640 Q40 V37 GMAT 2: 650 Q43 V36 GMAT 3: 600 Q47 V27 GPA: 3.3 WE: Management Consulting (Consulting) Let n~ be defined for all positive integers n as the remainder when (n [#permalink] ### Show Tags 05 Nov 2015, 04:57 4 17 00:00 Difficulty: 25% (medium) Question Stats: 70% (01:22) correct 30% (01:45) wrong based on 294 sessions ### HideShow timer Statistics Let n~ be defined for all positive integers n as the remainder when (n - 1)! is divided by n. What is the value of 32~ ? A. 0 B. 1 C. 2 D. 8 E. 31 _________________ KUDO me plenty ##### Most Helpful Community Reply Intern Joined: 21 Aug 2013 Posts: 3 Concentration: International Business, Leadership GPA: 2.9 WE: Programming (Computer Software) Re: Let n~ be defined for all positive integers n as the remainder when (n [#permalink] ### Show Tags 05 Nov 2015, 06:14 2 3 n~ = (n-1)! so 32~ = (32-1)! = 31! when 31!/32 we have 16*2 inside 31! hence 32 gets cancelled and we get remainder as 0 ##### General Discussion Current Student Joined: 12 Aug 2015 Posts: 2621 Schools: Boston U '20 (M) GRE 1: Q169 V154 Re: Let n~ be defined for all positive integers n as the remainder when (n [#permalink] ### Show Tags 16 Mar 2016, 00:57 2 32 = 8*4 which are both present in 31! so Remainder =0 hence A _________________ Director Joined: 12 Nov 2016 Posts: 725 Location: United States Schools: Yale '18 GMAT 1: 650 Q43 V37 GRE 1: Q157 V158 GPA: 2.66 Re: Let n~ be defined for all positive integers n as the remainder when (n [#permalink] ### Show Tags 15 Apr 2017, 12:39 1 Ok so I was initially not able to do this problem because I didn't understand how to divide 31!/32... Now that you guys have made the problem more clear I have a question- 5!/15 must be an integer? Because 5x4x3x2x1 contains the factors of 15 (5 x 3) When I do 17!/30 in a calculator the result is not an integer? Math Expert Joined: 02 Sep 2009 Posts: 52938 Re: Let n~ be defined for all positive integers n as the remainder when (n [#permalink] ### Show Tags 16 Apr 2017, 00:27 1 Nunuboy1994 wrote: Ok so I was initially not able to do this problem because I didn't understand how to divide 31!/32... Now that you guys have made the problem more clear I have a question- 5!/15 must be an integer? Because 5x4x3x2x1 contains the factors of 15 (5 x 3) When I do 17!/30 in a calculator the result is not an integer? First of all, 17!/30 = 11856247603200 = integer, but what 17!/30 has to do with this problem? _________________ Director Joined: 12 Nov 2016 Posts: 725 Location: United States Schools: Yale '18 GMAT 1: 650 Q43 V37 GRE 1: Q157 V158 GPA: 2.66 Re: Let n~ be defined for all positive integers n as the remainder when (n [#permalink] ### Show Tags 16 Apr 2017, 18:09 1 Bunuel wrote: Nunuboy1994 wrote: Ok so I was initially not able to do this problem because I didn't understand how to divide 31!/32... Now that you guys have made the problem more clear I have a question- 5!/15 must be an integer? Because 5x4x3x2x1 contains the factors of 15 (5 x 3) When I do 17!/30 in a calculator the result is not an integer? First of all, 17!/30 = 11856247603200 = integer, but what 17!/30 has to do with this problem? I trying to demonstrate the concept in this problem, which is new to me, in a different example- I think the calculator's notation just makes it appear as 1.something^e even though that doesn't necessarily mean it's not an integer. It's clear now. Math Expert Joined: 02 Sep 2009 Posts: 52938 Let n~ be defined for all positive integers n as the remainder when (n [#permalink] ### Show Tags 16 Apr 2017, 22:51 1 Nunuboy1994 wrote: Bunuel wrote: Nunuboy1994 wrote: Ok so I was initially not able to do this problem because I didn't understand how to divide 31!/32... Now that you guys have made the problem more clear I have a question- 5!/15 must be an integer? Because 5x4x3x2x1 contains the factors of 15 (5 x 3) When I do 17!/30 in a calculator the result is not an integer? First of all, 17!/30 = 11856247603200 = integer, but what 17!/30 has to do with this problem? I trying to demonstrate the concept in this problem, which is new to me, in a different example- I think the calculator's notation just makes it appear as 1.something^e even though that doesn't necessarily mean it's not an integer. It's clear now. For big numbers do not user calculator (unless it's not advanced) or Excell, use Wolframalpha: https://www.wolframalpha.com/ Hope it helps. _________________ Director Joined: 12 Nov 2016 Posts: 725 Location: United States Schools: Yale '18 GMAT 1: 650 Q43 V37 GRE 1: Q157 V158 GPA: 2.66 Re: Let n~ be defined for all positive integers n as the remainder when (n [#permalink] ### Show Tags 27 Jun 2017, 15:09 shasadou wrote: Let n~ be defined for all positive integers n as the remainder when (n - 1)! is divided by n. What is the value of 32~ ? A. 0 B. 1 C. 2 D. 8 E. 31 Simple- all this question is asking is if you have 31!/32 then what is the remainder? You don't necessarily have to expand 31!- 32 fits in because you have 16 and 2 so there is no remainder Thus "A" Retired Moderator Joined: 19 Mar 2014 Posts: 934 Location: India Concentration: Finance, Entrepreneurship GPA: 3.5 Re: Let n~ be defined for all positive integers n as the remainder when (n [#permalink] ### Show Tags 09 Jul 2017, 03:12 shasadou wrote: Let n~ be defined for all positive integers n as the remainder when (n - 1)! is divided by n. What is the value of 32~ ? A. 0 B. 1 C. 2 D. 8 E. 31 $$= \frac{(32-1)!}{32}$$ $$= \frac{31!}{32}$$ Numbers $$8 * 4 = 32$$, will cancel out the denomintor and hence the reminder will be ZERO. Hence, Answer is A _________________ "Nothing in this world can take the place of persistence. Talent will not: nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not: the world is full of educated derelicts. Persistence and determination alone are omnipotent." Best AWA Template: https://gmatclub.com/forum/how-to-get-6-0-awa-my-guide-64327.html#p470475 Study Buddy Forum Moderator Joined: 04 Sep 2016 Posts: 1299 Location: India WE: Engineering (Other) Let n~ be defined for all positive integers n as the remainder when (n [#permalink] ### Show Tags 10 Nov 2017, 03:20 Bunuel VeritasPrepKarishma 32! has various multiples of 32 built in say 8 * 4, 16* 2. Will not various no of multiples affect my remainder? For eg, even if 8*4 will cancel out 32 in denominator leaving remainder = 0, I still have one multiple of 16*2, correct? Target Test Prep Representative Status: Head GMAT Instructor Affiliations: Target Test Prep Joined: 04 Mar 2011 Posts: 2827 Re: Let n~ be defined for all positive integers n as the remainder when (n [#permalink] ### Show Tags 14 Nov 2017, 06:08 shasadou wrote: Let n~ be defined for all positive integers n as the remainder when (n - 1)! is divided by n. What is the value of 32~ ? A. 0 B. 1 C. 2 D. 8 E. 31 32~ = (32 - 1)!/32 = 31!/32 = 31!/2^5 Since we can safely say that there are at least five 2s in 31! (for example, 31! has the factors 16 = 2^4 and 8=2^3), the remainder is zero. Alternate Solution: 32~ = (32 - 1)!/32 = 31!/32 = 31!/2^5 We want to know the remainder when 31! is divided by 2^5. If we can establish that there are at least 5 factors of 2 in 31!, then we will know that 2^5 evenly divides into 31!, which means that the remainder would be 0. Let’s determine if we can find at least 5 twos in 31!: 31! = 31 x 30 x 29 x 28 x 27 x 26 x 25 x 24 x … x 1 31! = 31 x (2 x 15) x 29 x (2 X 2 x 14) x 27 x (2 x 13) x 25 x (2 x 2 x 2 x 3) x … x 1 Notice that we have found seven 2s, which is two more than what we needed. Thus, we know that 2^5 will evenly divide into 31!, leaving a remainder of 0. Answer: A _________________ Jeffery Miller Head of GMAT Instruction GMAT Quant Self-Study Course 500+ lessons 3000+ practice problems 800+ HD solutions Intern Joined: 18 Jun 2017 Posts: 49 GMAT 1: 660 Q39 V40 GMAT 2: 700 Q45 V41 Re: Let n~ be defined for all positive integers n as the remainder when (n [#permalink] ### Show Tags 30 Nov 2017, 22:24 Hi, So basically as long as there are enough prime factor powers in the numerator to cancel out all the prime factor powers in the denominator, the remainder is 0 correct? Math Expert Joined: 02 Sep 2009 Posts: 52938 Re: Let n~ be defined for all positive integers n as the remainder when (n [#permalink] ### Show Tags 30 Nov 2017, 23:04 calappa1234 wrote: Hi, So basically as long as there are enough prime factor powers in the numerator to cancel out all the prime factor powers in the denominator, the remainder is 0 correct? Yes. If the numerator contains the same (or more) primes as denominator and the (positive integer) powers of primes in the numerator are at least as big as the powers of the same primes in the denominator, then the result of the division will be an integer, so the remainder will be 0. _________________ EMPOWERgmat Instructor Status: GMAT Assassin/Co-Founder Affiliations: EMPOWERgmat Joined: 19 Dec 2014 Posts: 13551 Location: United States (CA) GMAT 1: 800 Q51 V49 GRE 1: Q170 V170 Re: Let n~ be defined for all positive integers n as the remainder when (n [#permalink] ### Show Tags 06 Feb 2018, 11:12 Hi All, This prompt is an example of a 'Symbolism' question - the prompt 'makes up' a math symbol, tells you what it means and asks you to perform a calculation using it. Based on the information in the prompt, we're told that.... 32~ is the remainder when (32-1)! is divided by 32. Now, there's no way that the GMAT would expect you to calculate the value of 31!, so we have to think in terms of what 31! actually is. Here's an example that's a bit easier to deal with: 4! = (4)(3)(2)(1) = 24 What numbers divide EVENLY into 24? 1, 2, 3, 4, 6, 8, 12 and 24 You can clearly see why 1, 2, 3 and 4 divide in - they're in the 'chain' of numbers that are multiplied together. 6 divides in because (2)(3) = 6 - and you can see the (2) and the (3) in the 'chain' Similarly, 8, 12 and 24 are also 'combinations' of the numbers in the 'chain', so they divide evenly in too. 31! has LOTS of numbers in it, so it's evenly divisibly by LOTS of different integers. If you were to write out 31!, you would see a (2) and a (16). This means that (2)(16) = 32 divides evenly into 31!, so there will be a remainder of 0. Final Answer: GMAT assassins aren't born, they're made, Rich _________________ 760+: Learn What GMAT Assassins Do to Score at the Highest Levels Contact Rich at: Rich.C@empowergmat.com # Rich Cohen Co-Founder & GMAT Assassin Special Offer: Save$75 + GMAT Club Tests Free
Official GMAT Exam Packs + 70 Pt. Improvement Guarantee
www.empowergmat.com/

*****Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!*****

VP
Joined: 09 Mar 2016
Posts: 1285
Let n~ be defined for all positive integers n as the remainder when (n  [#permalink]

### Show Tags

07 Feb 2018, 08:29
Bunuel wrote:
calappa1234 wrote:
Hi,

So basically as long as there are enough prime factor powers in the numerator to cancel out all the prime factor powers in the denominator, the remainder is 0 correct?

Yes. If the numerator contains the same (or more) primes as denominator and the (positive integer) powers of primes in the numerator are at least as big as the powers of the same primes in the denominator, then the result of the division will be an integer, so the remainder will be 0.

Hi Bunuel, long time no hear no see

Here is my solution.

to define if $$31!$$ is divisible by $$32$$ make prime factorization of $$32$$ so we get this --- > $$2^4$$

$$31!$$ certainly will have four $$2$$ as prime factors, hence $$\frac{31!}{32}$$ we get integer.

if this solution correct. What if similar question would have remainder - how could i find a remainder ?

thank you
Director
Joined: 09 Mar 2018
Posts: 986
Location: India
Re: Let n~ be defined for all positive integers n as the remainder when (n  [#permalink]

### Show Tags

10 Feb 2019, 18:51
Let n~ be defined for all positive integers n as the remainder when (n - 1)! is divided by n.

What is the value of 32~ ?

A. 0
B. 1
C. 2
D. 8
E. 31

32~ = 31!/31

Now if 31 from denominator is consumed completely this means that remainder is 0.

A
_________________

If you notice any discrepancy in my reasoning, please let me know. Lets improve together.

Quote which i can relate to.
Many of life's failures happen with people who do not realize how close they were to success when they gave up.

Re: Let n~ be defined for all positive integers n as the remainder when (n   [#permalink] 10 Feb 2019, 18:51
Display posts from previous: Sort by