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Marghe
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Multiple Ratios

by Marghe Fri Sep 06, 2013 10:45 am

Hello,

I am having problem to understand how to make a common term to solve multiple ratios.
I can not post the specific example for copyright reason, but I give another one from myself:

If I say, the ratio of green candies to red candies is 8 to 4, and the ratio of blue candies to green candies is 2 to 8. If the number of yellow candies to red candies is 3 to 4, what is the ratio of blue candies to yellow candies?

I do not understand how to find the common term to shape the new ratio.

Could you please help me.

Margherita Vittoria
mondegreen
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Re: Multiple Ratios

by mondegreen Fri Sep 06, 2013 3:21 pm

Marg Wrote:If I say, the ratio of green candies to red candies is 8 to 4, and the ratio of blue candies to green candies is 2 to 8. If the number of yellow candies to red candies is 3 to 4, what is the ratio of blue candies to yellow candies?


G:R = 8:4
B:G = 2:8
Y:R = 3:4
B:Y = ?

For every 8 greens,we have 4 reds. Again, for every 8 greens, we have 2 blues. Now, imagine that 8 greens is ONE unit. Thus, for the same ONE unit of green candy, I have 4 reds to every 2 blues, i.e. R:B = 4:2.

Again, similarly, for every 4 reds, I have 3 yellows. Thus, the final ratio of B:Y = 2:3.
Marghe
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Re: Multiple Ratios

by Marghe Sat Sep 07, 2013 7:59 am

Well, I did your same reasoning, but I am not sure that is the right one. I mean, it would been easier if the ratio involved just two variables.
Here we have 4 different candies, and I think we should use the merging process by multiplying the ratios and by finding the common term to match up.
That is why I am having trouble. I do not know how the common term comes up.
jnelson0612
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Re: Multiple Ratios

by jnelson0612 Sun Sep 08, 2013 2:05 pm

Marg Wrote:Well, I did your same reasoning, but I am not sure that is the right one. I mean, it would been easier if the ratio involved just two variables.
Here we have 4 different candies, and I think we should use the merging process by multiplying the ratios and by finding the common term to match up.
That is why I am having trouble. I do not know how the common term comes up.


Marg, I think that a different problem would help you understand this better. Please see this thread: marble-ratios-t4787.html

Read only the first post (the question) and then go right to the post by esledge, one of our instructors. She shows how to properly set up this kind of problem. Please check back here if you need more help.
Jamie Nelson
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Marghe
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Re: Multiple Ratios

by Marghe Sun Sep 08, 2013 2:29 pm

Thank you very much for posting the thread. That is what I needed to come up with the common multiple.

It seems the same process we use in fractions.




Best,

Margherita Vittoria
Last edited by Marghe on Sun Sep 08, 2013 2:49 pm, edited 1 time in total.
jnelson0612
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Re: Multiple Ratios

by jnelson0612 Sun Sep 08, 2013 2:49 pm

Great news! Thanks for letting me know. :-)
Jamie Nelson
ManhattanGMAT Instructor