December 14, 2018 December 14, 2018 09:00 AM PST 10:00 AM PST 10 Questions will be posted on the forum and we will post a reply in this Topic with a link to each question. There are prizes for the winners. December 14, 2018 December 14, 2018 10:00 PM PST 11:00 PM PST Carolyn and Brett  nicely explained what is the typical day of a UCLA student. I am posting below recording of the webinar for those who could't attend this session.
Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 51214

What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
15 Oct 2012, 03:53
Question Stats:
72% (01:33) correct 28% (01:26) wrong based on 1640 sessions
HideShow timer Statistics




Math Expert
Joined: 02 Sep 2009
Posts: 51214

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
15 Oct 2012, 03:53




Senior Manager
Joined: 24 Aug 2009
Posts: 469
Schools: Harvard, Columbia, Stern, Booth, LSB,

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
15 Oct 2012, 03:59
1) Let of no of coins with Claire = 2x Let of no of coins with Bert = 3x 2x+3x = 5x >x can take any value  Insufficient 2) No of coins can take any integer value from 21 to 28 Insufficient 1+2) Total no of coins must be a multiple of 5 & between 21 & 28. Only possible integer value is 25>Sufficient Answer C
_________________
If you like my Question/Explanation or the contribution, Kindly appreciate by pressing KUDOS. Kudos always maximizes GMATCLUB worth Game Theory
If you have any question regarding my post, kindly pm me or else I won't be able to reply




Manager
Joined: 29 Apr 2012
Posts: 79
Location: United States
Concentration: International Business, Real Estate
GMAT Date: 10222012

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
15 Oct 2012, 05:39
Bunuel wrote: What is the total number of coins that Bert and Claire have?
(1) Bert has 50 percent more coins than Claire. (2) The total number of coins that Bert and Claire have is between 21 and 28.
let the total number of coins be t. Stamnt A: B = 1.5C > not sufficient Statment B: 21<B+C <28 usinng both: T = B+C = c+1.5c =2.5c now: anythig between 21 and 28 which is a multiple of 2.5 is 22.5/25/27.5 Since coins cannot be in decimal points , we are left with only one option that is t=25. thus, OA: C using both A and B together Whats the OA?



VP
Joined: 02 Jul 2012
Posts: 1176
Location: India
Concentration: Strategy
GPA: 3.8
WE: Engineering (Energy and Utilities)

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
15 Oct 2012, 08:44
1) Bert can have 10, Claire can have 15 OR Bert can have 20, Claire can have 30. Not sufficient. 2) Clearly not sufficient Both together 1.5 B + B = 2.5 B= x. The only number in the range to give an integer value for B is 25. So, answer is C
_________________
Did you find this post helpful?... Please let me know through the Kudos button.
Thanks To The Almighty  My GMAT Debrief
GMAT Reading Comprehension: 7 Most Common Passage Types



Manager
Joined: 21 Sep 2012
Posts: 198

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
16 Oct 2012, 04:47
We need to find out B + C
statement 1
B=0.5C+C
insufficient can't get a value
statement 2
21<B+C<28 again no value insufficient
combining 1 and 2
21<1.5C+C<28 21<2.5C<28 ( multiply by 2) 42<5C<56
so now the values for 5c are the multiples between 42 and 56 so we have 3 values
5C=45 >>> C=9 5C=50 >>> C=10 5C=55 >>> C=11
but we need to satisfy the condition that B=1.5C this is only possible when C = 10 since we need an integer value so 11 and 9 are ruled out
B+C=10+15=25
So the answer is C.



Director
Status: Done with formalities.. and back..
Joined: 15 Sep 2012
Posts: 595
Location: India
Concentration: Strategy, General Management
Schools: Olin  Wash U  Class of 2015
WE: Information Technology (Computer Software)

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
16 Oct 2012, 05:04
If Bert has B coins and Claire has C coins. Then total number of coins =B+C From Statement 1 B =1.5 C or B/C=3/2 Ratio of B and C is 3:2 => Only inference from this we can make is, total number must be a multiple of 5. Not sufficient From statement 2 21<=B+C<=28 Multiple values for B+C  not sufficient Combining the information from statement 1 and 2. Total number of coins = 25 Hence C. Bunuel wrote: What is the total number of coins that Bert and Claire have? (1) Bert has 50 percent more coins than Claire. (2) The total number of coins that Bert and Claire have is between 21 and 28. Practice Questions Question: 65 Page: 280 Difficulty: 600
_________________
Lets Kudos!!! Black Friday Debrief



Math Expert
Joined: 02 Sep 2009
Posts: 51214

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
19 Oct 2012, 04:46



Manager
Joined: 12 Jan 2013
Posts: 153

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
10 Jan 2014, 07:51
Bunuel wrote: What is the total number of coins that Bert and Claire have? (1) Bert has 50 percent more coins than Claire. (2) The total number of coins that Bert and Claire have is between 21 and 28. Practice Questions Question: 65 Page: 280 Difficulty: 600 The stem asks us: B + C = TC, what is TC? 1) This tells us that B = 1.5 C, so now we have two unknowns: 2.5C = TC, insufficient 2) Gives us a range of possible values, so in itself 2 is insufficient because the value could be any of 6 values. Insufficient 1 + 2 : Look closely: given our equation from 1, TC must be a multiple of 5 (we cannot have fractions of coins), and given the restriction in 2, we only have ONE possible multiple of 5: 25... So, TC = 25... Answer is C.



EMPOWERgmat Instructor
Status: GMAT Assassin/CoFounder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 13081
Location: United States (CA)

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
12 Mar 2015, 17:07
Hi All, On Test Day, you're going to face a few questions in the Quant section that are perfect for "brute force"  you don't have to be a genius to get the correct answer and you don't need to have any specialized knowledge either. You DO have to put pen to pad and do some basic work though. Here, we're asked for the total number of coins that Bert and Clair have. Fact 1: Bert has 50 percent more coins than Claire. Since you can't have a "fraction" of a coin, this piece of information provides just a little bit of info about the relationship between the number of coins that Bert has and the number of coins that Claire has. IF..... Claire has 1 coin, Bert has 1.5 coins, which does NOT make sense (he can't have half a coin). Claire has 2 coins, then Bert has 3 coins. THIS makes sense. The total is 5 coins. Claire has 4 coins, then bert has 6 coins. This also makes sense. The total is 10 coins. Fact 1 is INSUFFICIENT. You may have noticed that the total number of coins is going to be a multiple of 5. You don't need to know that to answer the question (although it would likely save you some time later on). Fact 2: The total number of coins that Bert and Claire have is between 21 and 28. This gives us more direct information, but no exact value. Fact 2 is INSUFFICIENT. Combined, we know.... Bert has 50 percent more coins than Claire. The total number of coins that Bert and Claire have is between 21 and 28. From here, you can "map out" the possibilities.... We already know that Claire MUST have an EVEN number of coins....so let's start there.... IF... Claire = 6, then Bert = 9 and the total is 15. This does not fit the given range, so it can't be the answer. Claire = 8, then Bert = 12 and the total is 20. This does not fit the given range, so it can't be the answer. Claire = 10, then Bert = 15 and the total is 25. This DOES fit the given range, so it COULD be the answer. Claire = 12, then Bert = 18 and the total is 30. This does not fit the given range, so it can't be the answer. As the number of coins Claire has increases, then the total will increase (and continue to be out of the given range). This means that there's JUST ONE answer that fits all of the given information. Combined, SUFFICIENT. 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
CoFounder & 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!*****



Manager
Joined: 15 Mar 2015
Posts: 111

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
16 May 2015, 08:34
B+C? (1) B=1.5C. Clearly insufficient. (2) 21<B+C<28 As we are working with integers, we can rule out 21 and 28. Thus: 22=<B+C=<27. This is still insufficient, though. As we still have 6 possibilities. (1)+(2) B+C should be divisible by 5/2. Because B+C = 2,5C and as we are working with countable items, we want to find an integer. As such. We will have: Tot/(5/2)=Tot*2/5=2*tot/5 = integer. To be divisible by 5, the number has to end in 5 or 0. For this reason I will only look at the unit digits. (2>7) 4,6,8,0,2,4. Only one out of the seven possibilities ended in 0 or 5, and thus only one possibility exists. C is sufficient. (This looks as if it takes a lot of time, but it's not very time consuming when done in your head)
_________________
I love being wrong. An incorrect answer offers an extraordinary opportunity to improve.



Director
Joined: 10 Mar 2013
Posts: 503
Location: Germany
Concentration: Finance, Entrepreneurship
GPA: 3.88
WE: Information Technology (Consulting)

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
31 May 2015, 02:43
B+C = ? 1) C + 1,5C = 2,5C Not sufficient 2) Clearly no sufficient. We need a relationship between B and C to make it work 1+2) 2,5C = 2128 C = (2128)*2/5, so we need a multiple of 5 > 25*2 is the only mulstiple of 5 in the range 21  28
_________________
When you’re up, your friends know who you are. When you’re down, you know who your friends are.
Share some Kudos, if my posts help you. Thank you !
800Score ONLY QUANT CAT1 51, CAT2 50, CAT3 50 GMAT PREP 670 MGMAT CAT 630 KAPLAN CAT 660



Intern
Joined: 29 Jun 2015
Posts: 12
Concentration: Finance, Strategy
GPA: 2.8

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
07 Jul 2015, 01:04
I tried the estimation strategy and I have 2 possible solutions that match the criterion. If they have 16 and 8 coins or they have 18 and 9 coins. Need help understanding the same.



Math Expert
Joined: 02 Sep 2009
Posts: 51214

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
07 Jul 2015, 01:08



Current Student
Joined: 12 Jan 2016
Posts: 11
GPA: 3.74

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
08 Mar 2016, 18:35
fameatop wrote: 1) Let of no of coins with Claire = 2x Let of no of coins with Bert = 3x 2x+3x = 5x >x can take any value  Insufficient
2) No of coins can take any integer value from 21 to 28 Insufficient
1+2) Total no of coins must be a multiple of 5 & between 21 & 28. Only possible integer value is 25>Sufficient Answer C I did this question the same way that fametop did, can anyone comment on if this is a good way to think about it. In terms of total coins needing to be a multiple of 5?



CEO
Joined: 20 Mar 2014
Posts: 2633
Concentration: Finance, Strategy
GPA: 3.7
WE: Engineering (Aerospace and Defense)

What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
08 Mar 2016, 18:50
grainflow wrote: fameatop wrote: 1) Let of no of coins with Claire = 2x Let of no of coins with Bert = 3x 2x+3x = 5x >x can take any value  Insufficient
2) No of coins can take any integer value from 21 to 28 Insufficient
1+2) Total no of coins must be a multiple of 5 & between 21 & 28. Only possible integer value is 25>Sufficient Answer C I did this question the same way that fametop did, can anyone comment on if this is a good way to think about it. In terms of total coins needing to be a multiple of 5? Yes, this is a perfectly valid method for attacking this question. Alternately, once you realize that B=1.5C and 21 < B+C < 28 > 21< 2.5C<28, remember that the total number of coins MUST be an integer. Thus the final value must be a multiple of 2.5 > 25 is the ONLY value. Hence C is the correct answer Hope this helps.



Current Student
Joined: 12 Jan 2016
Posts: 11
GPA: 3.74

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
08 Mar 2016, 18:57
Understood. This method just seemed so much easier than the other I wanted to make sure I was not overlooking something.



VP
Joined: 09 Mar 2016
Posts: 1218

Re: What is the total number of coins that Bert and Claire have?
[#permalink]
Show Tags
17 Aug 2018, 09:43
Bunuel wrote: SOLUTION
What is the total number of coins that Bert and Claire have?
Question: \(B+C=?\)
(1) Bert has 50 percent more coins than Claire > \(B=1.5C\). Not sufficient.
(2) The total number of coins that Bert and Claire have is between 21 and 28 > \(21<B+C<28\). Not sufficient.
(1)+(2) Since from (1) \(B=1.5C\) and from (2) \(21<B+C<28\), then \(21<1.5C+C<28\) > \(21<2.5C<28\). Three values of C satsify this inequality; 9, 10, and 11. But for 9 and 11, the value of B from \(B=1.5C.\) won't be an integer, thus C can only be 10 > \(B=1.5C=15\) > \(B+C=25\). Sufficient.
Answer: C. wow, Bunuel brilliant solution




Re: What is the total number of coins that Bert and Claire have? &nbs
[#permalink]
17 Aug 2018, 09:43






