 It is currently 30 Nov 2020, 18:19 ### 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

#### Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here. # a, b, and c are multiples of 15 and a < b < c  Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:
Director  Joined: 16 May 2014
Posts: 597
GRE 1: Q165 V161 Followers: 116

Kudos [?]: 685 , given: 64

GRE Math Challenge #8- a, b and c are multiple of 15 [#permalink]
Expert's post 00:00

Question Stats: 64% (00:59) correct 35% (01:14) wrong based on 105 sessions
a, b and c are multiples of 15, and 0 < a < b < c

 Quantity A Quantity B The remainder when b is divided by c The remainder when (b + c) is divided by a

A) The quantity in Column A is greater.
B) The quantity in Column B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.
[Reveal] Spoiler: OA

_________________

My GRE Resources
Free GRE resources | GRE Prep Club Quant Tests
If you find this post helpful, please press the kudos button to let me know ! Intern Joined: 19 Sep 2016
Posts: 1
Followers: 0

Kudos [?]: 0 , given: 0

Re: GRE Math Challenge #8- a, b and c are multiple of 15 [#permalink]
hi

Thanks
Intern Joined: 02 Jul 2016
Posts: 25
Followers: 0

Kudos [?]: 15 , given: 2

Re: GRE Math Challenge #8- a, b and c are multiple of 15 [#permalink]
I think the answer is D. I took 15,30 and 45 at first and here A is greater. But then I took 15, 30 and 150 30/150 leaves a quotient of 0.2 and a remainder of 0. Hence D GRE Instructor Joined: 10 Apr 2015
Posts: 3914
Followers: 164

Kudos [?]: 4781  , given: 70

Re: GRE Math Challenge #8- a, b and c are multiple of 15 [#permalink]
3
KUDOS
Expert's post
Given: a < b < c

Quantity A: The remainder when b is divided by c
Notice that c is greater than b
So, b divided by c will equal 0 with remainder b
If this isn't 100% clear, here are a few examples.
4 divided by 6 equals 0 with remainder 4.
Likewise, 2 divided by 7 equals 0 with remainder 2.
So, we get.....
Quantity A: b

Quantity B: The remainder when (b + c) is divided by a
IMPORTANT CONCEPT
When positive integer N is divided by positive integer D, the remainder R is such that 0 < R < D
For example, if we divide some positive integer by 7, the remainder will be 6, 5, 4, 3, 2, 1, or 0
So, we can conclude that....
Quantity B: some integer that's less than a

Since it's given that a < b, we can be certain that quantity A is greater.

[Reveal] Spoiler:
A

RELATED VIDEO

_________________

Brent Hanneson – Creator of greenlighttestprep.com Retired Moderator Joined: 07 Jun 2014
Posts: 4803
GRE 1: Q167 V156 WE: Business Development (Energy and Utilities)
Followers: 175

Kudos [?]: 3037 , given: 394

a, b, and c are multiples of 15 and a < b < c [#permalink]
Expert's post
a, b, and c are multiples of 15 and a < b < c

 Quantity A Quantity B The remainder when b is divided by c The remainder when (b + c) is divided by a

A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.

Drill 2
Question: 2
Page: 290

_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

Retired Moderator Joined: 07 Jun 2014
Posts: 4803
GRE 1: Q167 V156 WE: Business Development (Energy and Utilities)
Followers: 175

Kudos [?]: 3037 , given: 394

Re: a, b, and c are multiples of 15 and a < b < c [#permalink]
Expert's post
Explanation

Try Plugging In. If a = 15, b = 30, and c = 60, Quantity A is 30 because c cannot divide into b even one time. Quantity B is 0 because 90 divided by 15 has no remainder. Eliminate choices (B) and (C).

Try a new set of numbers to further narrow your choices. If a = 30, b = 45, and c = 120, Quantity A is 45, and Quantity B is 15. The answer is choice A.
_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

Intern Joined: 06 Oct 2016
Posts: 7
Followers: 0

Kudos [?]: 1 , given: 1

Re: GRE Math Challenge #8- a, b and c are multiple of 15 [#permalink]
i think the answer will be D, when I take 15, 30, 45 then for the A quantity remainder will be 15, and for B is 0, then A is BIG, but if I take 15, 30, 150 ( i can take this, cause You didnt tell me that it will be consecutive multiples) then the remainder will be 0 for the quantity A and B, then the answer ll be D! Can you explain it? Manager Joined: 27 Sep 2017
Posts: 111
Followers: 1

Kudos [?]: 47  , given: 4

Re: a, b, and c are multiples of 15 and a < b < c [#permalink]
1
KUDOS
sandy wrote:
Explanation

Try Plugging In. If a = 15, b = 30, and c = 60, Quantity A is 30 because c cannot divide into b even one time. Quantity B is 0 because 90 divided by 15 has no remainder. Eliminate choices (B) and (C).

Try a new set of numbers to further narrow your choices. If a = 30, b = 45, and c = 120, Quantity A is 45, and Quantity B is 15. The answer is choice A.

When it comes to this question, don't we need to consider negative numbers?

If we do, what the result will be?
Retired Moderator Joined: 07 Jun 2014
Posts: 4803
GRE 1: Q167 V156 WE: Business Development (Energy and Utilities)
Followers: 175

Kudos [?]: 3037 , given: 394

Re: a, b, and c are multiples of 15 and a < b < c [#permalink]
Expert's post
This is a good question..

All the questions I have encountered have positive numbers when asking for remainder.

Remainder is a positive number. So Say $$-11 \div 5$$ has a remainder of 4 not -1.

Let me look around and get back to you on this one.
_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

Intern Joined: 27 Aug 2018
Posts: 1
Followers: 0

Kudos [?]: 0 , given: 0

Re: a, b, and c are multiples of 15 and a < b < c [#permalink]
when dealing with these types of questions we usually consider negative numbers as well. So why we are not considering negative numbers in this question? GRE Instructor Joined: 10 Apr 2015
Posts: 3914
Followers: 164

Kudos [?]: 4781  , given: 70

Re: a, b, and c are multiples of 15 and a < b < c [#permalink]
3
KUDOS
Expert's post
sandy wrote:
a, b, and c are multiples of 15 and a < b < c

 Quantity A Quantity B The remainder when b is divided by c The remainder when (b + c) is divided by a

A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.

Drill 2
Question: 2
Page: 290

Remainder rule:
When positive integer N is divided by positive integer D, the remainder R is such that 0 ≤ R < D
For example, if we divide some positive integer by 7, the remainder will be 6, 5, 4, 3, 2, 1, or 0

QUANTITY A: The remainder when b is divided by c
Since c is greater than b, we know that: b divided by c equals zero with remainder b
For example, 30 divided by 75 equals 0 with remainder 30
So, QUANTITY A = b

QUANTITY B: The remainder when (b + c) is divided by a
According to the above rule, the remainder must be LESS THAN a
So, QUANTITY B = some number less than a

We have:
QUANTITY A: b
QUANTITY B: some number less than a
Since we are told that a < b < c, we can see that Quantity A is greater.

RELATED VIDEO FROM OUR COURSE

_________________

Brent Hanneson – Creator of greenlighttestprep.com Manager  Joined: 19 Nov 2018
Posts: 102
Followers: 0

Kudos [?]: 108 , given: 53

Re: GRE Math Challenge #8- a, b and c are multiple of 15 [#permalink]
Given we use 15, 30 and 45 for our sample numbers we could have

A

$$\frac{30}{45}$$ which, although not conventionally done, could be expressed as mixed fraction, like so:

$$0\frac{30}{45}$$ which shows that 45 goes into 30 zero times and leaves a remainder of 30.

B

We have $$\frac{75}{15}$$, which becomes

$$5\frac{0}{15}$$, which shows that 15 goes into 75 five times and leaves 0 remainder.

We can see that the remainder for A(30) is greater than the remainder for B(0). GRE Instructor Joined: 10 Apr 2015
Posts: 3914
Followers: 164

Kudos [?]: 4781  , given: 70

Re: GRE Math Challenge #8- a, b and c are multiple of 15 [#permalink]
1
KUDOS
Expert's post
IlCreatore wrote:

This is right instead. 0 divided by any number is 0 with remainder of zero and the definition of multiple does not forbid to look for negative multiples, unless stated we are using positive multiples. So the Answer should be D.

Does anybody have the OA/OE?

Good point. The question does not state that a, b and c are POSITIVE multiples.
I never noticed that the first time I read the question.

When it comes to remainder/divisibility questions on the GRE, there will always be some proviso that states the values are positive integers.
In my opinion, it's a bad question.

I'm going to edit the question so that it has the required provisos.

Cheers,
Brent
_________________

Brent Hanneson – Creator of greenlighttestprep.com  Intern Joined: 29 Mar 2020
Posts: 1
Followers: 0

Kudos [?]: 1  , given: 0

Re: a, b, and c are multiples of 15 and a < b < c [#permalink]
1
KUDOS
consider a=15, b=30, c=45

Quantity A = b/c = 30/45, Remainder = 30

Quantity B = (b+c)/a = 75/15, Remainder = 0

Quantity A is greater

option A should be the answer
Manager Joined: 15 May 2020
Posts: 85
Followers: 1

Kudos [?]: 47 , given: 4

Re: a, b, and c are multiples of 15 and a < b < c [#permalink]
We have to remember that the remainder of a/c when a is less than c is equals to a.

With this condition. A = b, because b is less than c. And B = 0, because the remainder of the division of multiples of the same number is 0.

Since b is greater than 0, the correct answer is A. Re: a, b, and c are multiples of 15 and a < b < c   [#permalink] 12 Jun 2020, 16:57
Display posts from previous: Sort by

# a, b, and c are multiples of 15 and a < b < c  Question banks Downloads My Bookmarks Reviews Important topics  Powered by phpBB © phpBB Group Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.