Problem Solving

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]

Can someone explain how the answer is 45

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]

Black:Green:Red = 2:1:2.
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.

GMATGuruNY wrote:

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]

Black:Green:Red = 2:1:2.
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.

Yes this is very correct but there can be a case where we have
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.

sameerballani wrote:

GMATGuruNY wrote:

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]

Black:Green:Red = 2:1:2.
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.

Yes this is very correct but there can be a case where we have
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.

The total number of each color must comply with the given ratio of B:G:R = 2:1:2.
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.