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A jar contains marbles of 3 colors [#permalink]
27 Aug 2016, 01:12

00:00

Question Stats:

42% (01:39) correct
57% (01:37) wrong based on 21 sessions

A jar contains only marbles of three different colors : red,green and yellow.The red and green marbles are in the ratio of 2:5 and the yellow and red marbles are in a ratio of 5:6.Which of the following could be the total number of marbles?

Re: A jar contains marbles of 3 colors [#permalink]
29 Aug 2016, 14:48

1

This post received KUDOS

Expert's post

yasir9909 wrote:

A jar contains only marbles of three different colors : red,green and yellow.The red and green marbles are in the ratio of 2:5 and the yellow and red marbles are in a ratio of 5:6.Which of the following could be the total number of marbles?

Our goal here is to COMBINE both ratios: R:G = 2:5 and Y:R = 5:6 Since both ratios have a number of RED marbles, we'll use this value to combine the ratios. To do so, we need to rewrite one ratio (or possibly both ratios) as an equivalent ratio, so that the resulting ratio shares a RED value with the other given ratio.

So, take the first ratio of R:G (2:5) and multiply both quantities by 3 to get: R:G = 6:15 So, we now have the ratios Y:R = 5:6 AND R:G = 6:15 We can COMBINE them to get Y:R:G = 5:6:15

So, we could have 5 yellows, 6 reds, and 15 greens for a total of 26 marbles Or, we could have 10 yellows, 12 reds, and 30 greens for a total of 52 marbles Or we could have 15 yellows, 18 reds, and 45 greens for a total of 78 marbles etc. As you can see, the totals are all multiples of 26.

Since answer choices A and F are the ONLY multiples of 26, they are the correct answers.

Re: A jar contains marbles of 3 colors [#permalink]
06 Sep 2017, 05:36

I think your answers should be combined. Given the fact that the ratio is 5:6:15, the sum of 5+6+15 = 26. Thus, we should look for multiples of 26 that are 13 = 26*1/2, 52 = 26*2 and 182 = 26*7. To conclude the answers are A, C and F. Am I right?

Re: A jar contains marbles of 3 colors [#permalink]
18 Sep 2017, 02:01

IlCreatore wrote:

I think your answers should be combined. Given the fact that the ratio is 5:6:15, the sum of 5+6+15 = 26. Thus, we should look for multiples of 26 that are 13 = 26*1/2, 52 = 26*2 and 182 = 26*7. To conclude the answers are A, C and F. Am I right?

Thinking about this question again, I found out that the right answers are those of yasir because 13 is not a multiple of 26 since a multiple is defined as an integer number that is product of two integers and 1/2 is not an integer.

Re: A jar contains marbles of 3 colors [#permalink]
18 Sep 2017, 14:00

1

This post received KUDOS

Expert's post

IlCreatore wrote:

I think your answers should be combined. Given the fact that the ratio is 5:6:15, the sum of 5+6+15 = 26. Thus, we should look for multiples of 26 that are 13 = 26*1/2, 52 = 26*2 and 182 = 26*7. To conclude the answers are A, C and F. Am I right?

Answer choice A is not correct. 13 is not a multiple of 26.

Multiples of 26 are in the form 26k, where k is an INTEGER So, the multiples of 26 are as follows: {. . ., -78, -52, -26, 0, 26, 52, 78, 104, . . . }

Cheers, Brent
_________________

Brent Hanneson – Creator of greenlighttestprep.com Sign up for my free GRE Question of the Dayemails

Re: A jar contains marbles of 3 colors [#permalink]
25 Sep 2017, 04:37

GreenlightTestPrep wrote:

IlCreatore wrote:

I think your answers should be combined. Given the fact that the ratio is 5:6:15, the sum of 5+6+15 = 26. Thus, we should look for multiples of 26 that are 13 = 26*1/2, 52 = 26*2 and 182 = 26*7. To conclude the answers are A, C and F. Am I right?

Answer choice A is not correct. 13 is not a multiple of 26.

Multiples of 26 are in the form 26k, where k is an INTEGER So, the multiples of 26 are as follows: {. . ., -78, -52, -26, 0, 26, 52, 78, 104, . . . }

Cheers, Brent

Exactly as I wrote in my second comment. Your previous answer was wrong, yasir was right.