A diagram has exactly two black dots and one green dot for every two red dots. There are no dots of any other color in the diagram. Which of the following could be the number of dots in the diagram?
A 3
B 18
C 36
D 45
E 52
[spoiler]
OA: D
Source:Kaplan
I am sure, We need to change the language of this question. There seems to be multiple correct answers present[/spoiler]
two black dots and one green dot
This topic has expert replies
-
- Legendary Member
- Posts: 544
- Joined: Mon Dec 27, 2010 8:10 am
- Thanked: 45 times
- Followed by:2 members
- itsmebharat
- Master | Next Rank: 500 Posts
- Posts: 150
- Joined: Tue Aug 18, 2009 7:36 am
- Location: gurgaon
- Thanked: 8 times
- Followed by:2 members
Can someone explain how the answer is 45
I am not an Expert, please feel free to suggest if there is an error.
- GMATGuruNY
- GMAT Instructor
- Posts: 15539
- Joined: Tue May 25, 2010 12:04 pm
- Location: New York, NY
- Thanked: 13060 times
- Followed by:1906 members
- GMAT Score:790
Black:Green:Red = 2:1:2.sameerballani wrote:A diagram has exactly two black dots and one green dot for every two red dots. There are no dots of any other color in the diagram. Which of the following could be the number of dots in the diagram?
A 3
B 18
C 36
D 45
E 52
[spoiler]
OA: D
Source:Kaplan
I am sure, We need to change the language of this question. There seems to be multiple correct answers present[/spoiler]
Thus, the number of dots must be a multiple of 2+1+2=5.
Only answer choice D is a multiple of 5.
The correct answer is D.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
-
- Legendary Member
- Posts: 544
- Joined: Mon Dec 27, 2010 8:10 am
- Thanked: 45 times
- Followed by:2 members
Yes this is very correct but there can be a case where we haveGMATGuruNY wrote:Black:Green:Red = 2:1:2.sameerballani wrote:A diagram has exactly two black dots and one green dot for every two red dots. There are no dots of any other color in the diagram. Which of the following could be the number of dots in the diagram?
A 3
B 18
C 36
D 45
E 52
[spoiler]
OA: D
Source:Kaplan
I am sure, We need to change the language of this question. There seems to be multiple correct answers present[/spoiler]
Thus, the number of dots must be a multiple of of 2+1+2=5.
Only answer choice D is a multiple of 5.
The correct answer is D.
2*7= 14 red balls and consequently 3*7= 21 red balls. Hence total umber of balls=35(basically multiple of 5)
But then we can also add ONLY 1 RED BALL, making the total count=36. (Because the condition states:A diagram has exactly two black dots and one green dot for every two red dots. Nothing is mentioned for a single red dot.)
Rather i feel this question is probably in complete.
While writing all this, I feel we can even add one black+one green +one red. that makes 18 also the correct answer without breaking the given condition..
I feel there can be many Combinations possible unless we make sure we don't break the condition mentioned.
What you feel?
Thanks.
- GMATGuruNY
- GMAT Instructor
- Posts: 15539
- Joined: Tue May 25, 2010 12:04 pm
- Location: New York, NY
- Thanked: 13060 times
- Followed by:1906 members
- GMAT Score:790
The total number of each color must comply with the given ratio of B:G:R = 2:1:2.sameerballani wrote:Yes this is very correct but there can be a case where we haveGMATGuruNY wrote:Black:Green:Red = 2:1:2.sameerballani wrote:A diagram has exactly two black dots and one green dot for every two red dots. There are no dots of any other color in the diagram. Which of the following could be the number of dots in the diagram?
A 3
B 18
C 36
D 45
E 52
[spoiler]
OA: D
Source:Kaplan
I am sure, We need to change the language of this question. There seems to be multiple correct answers present[/spoiler]
Thus, the number of dots must be a multiple of of 2+1+2=5.
Only answer choice D is a multiple of 5.
The correct answer is D.
2*7= 14 red balls and consequently 3*7= 21 red balls. Hence total umber of balls=35(basically multiple of 5)
But then we can also add ONLY 1 RED BALL, making the total count=36. (Because the condition states:A diagram has exactly two black dots and one green dot for every two red dots. Nothing is mentioned for a single red dot.)
Rather i feel this question is probably in complete.
While writing all this, I feel we can even add one black+one green +one red. that makes 18 also the correct answer without breaking the given condition..
I feel there can be many Combinations possible unless we make sure we don't break the condition mentioned.
What you feel?
Thanks.
If there are 14 red dots, then B:G:R = 14:7:14, yielding 14+7+14 = 35 dots.
If another red dot is added, then B:G:R = 14:7:15, which is not a ratio of 2:1:2.
We cannot add a single red dot.
To maintain the ratio, the total number of dots can be increased only by a multiple of 5.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
GMAT/MBA Expert
- lunarpower
- GMAT Instructor
- Posts: 3380
- Joined: Mon Mar 03, 2008 1:20 am
- Thanked: 2256 times
- Followed by:1535 members
- GMAT Score:800
just to clarify, in a way that "fits on a business card":
"____ for every ____" is a standard way of writing a RATIO.
thus, if there is an X for every 2 Y's, then that means that the ratio of X's to Y's is exactly 1:2 -- no exceptions.
learn this; remember it; it's a very standard way to write ratios.
"____ for every ____" is a standard way of writing a RATIO.
thus, if there is an X for every 2 Y's, then that means that the ratio of X's to Y's is exactly 1:2 -- no exceptions.
learn this; remember it; it's a very standard way to write ratios.
Ron has been teaching various standardized tests for 20 years.
--
Pueden hacerle preguntas a Ron en castellano
Potete chiedere domande a Ron in italiano
On peut poser des questions à Ron en français
Voit esittää kysymyksiä Ron:lle myös suomeksi
--
Quand on se sent bien dans un vêtement, tout peut arriver. Un bon vêtement, c'est un passeport pour le bonheur.
Yves Saint-Laurent
--
Learn more about ron
--
Pueden hacerle preguntas a Ron en castellano
Potete chiedere domande a Ron in italiano
On peut poser des questions à Ron en français
Voit esittää kysymyksiä Ron:lle myös suomeksi
--
Quand on se sent bien dans un vêtement, tout peut arriver. Un bon vêtement, c'est un passeport pour le bonheur.
Yves Saint-Laurent
--
Learn more about ron