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darla
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Word Problems GRE Strategy Guide - Hard Questions #13

by darla Tue Jun 19, 2012 11:26 am

My question is about the Word Problems GRE Strategy Guide 2nd Edition - Practice Question Sets in back of the book - Hard practice question solutions #13.

It says 24D = 15M, which I agree with. It says it is turning the equation into the "ratio of muxes to darbles." Why does the solution then go on to do M/D = 24/15? I don't understand why it's 24/15 and not 15/24.
cesarcontrerasg
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Re: Word Problems GRE Strategy Guide - Hard Questions #13

by cesarcontrerasg Wed Jun 20, 2012 12:24 am

Hi,

I'm also a student, but I guess I know the answer.

It is because 24 Darbles are equal to 15 Muxes... Therefore, if we want to know the ratio of Muxes to Darbles, we should use the information given in the equation as follows:

24D = 15M or 15M = 24D, then
M = 24/15 D, then
M/D = 24/15 and this is the answer!

Let's wait for one of the experts to validate my explanation!

Best,
esledge
 
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Re: Word Problems GRE Strategy Guide - Hard Questions #13

by esledge Sun Jun 24, 2012 1:33 pm

Consider your explanation validated, Cesar!

I think your step-by-step math is the best way to prove this, but I'll add another, more word-oriented explanation.

If 24 darbles equal 15 muxes, each darble is worth LESS and each muxes is worth MORE. (You need more of the cheap darbles to buy fewer of the relatively expensive muxes.)

So an M/D ratio is a [cost MORE/cost LESS] ratio, which would be >1.