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# If w/x = 2/3 and w/y = 8/15, then (x + y)/y =

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Re: If w/x = 2/3 and w/y = 8/15, then (x + y)/y = [#permalink]
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Hi All,

While many Test Takers would go about solving this problem with Algebra, TESTing VALUES provides an easy approach.

We're told that W/X = 2/3 and W/Y = 8/15

Given these two ratios, we know that W is a multiple of 2 and a multiple of 8. The simplest value for W is 8....

W = 8
X = 12
Y = 15

Using these values, we can now answer the question: (X+Y)/Y = .....

(12 + 15)/15 = 27/15 = 9/5

GMAT assassins aren't born, they're made,
Rich
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Re: If w/x = 2/3 and w/y = 8/15, then (x + y)/y = [#permalink]
EMPOWERgmatRichC wrote:
Hi All,

While many Test Takers would go about solving this problem with Algebra, TESTing VALUES provides an easy approach.

We're told that W/X = 2/3 and W/Y = 8/15

Given these two ratios, we know that W is a multiple of 2 and a multiple of 8. The simplest value for W is 8....

W = 8
X = 12
Y = 15

Using these values, we can now answer the question: (X+Y)/Y = .....

(12 + 15)/15 = 27/15 = 9/5

GMAT assassins aren't born, they're made,
Rich

I took the same approach, however by finding the LCM of all the numbers involved you aren't necessarily "testing" numbers. The integer you found WILL work.
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Re: If w/x = 2/3 and w/y = 8/15, then (x + y)/y = [#permalink]
Hi ak1802,

I didn't have to use the LCM; I chose to TEST VALUES that were the easiest AND fit the 'restrictions' that we were given. In a 'TEST VALUES' prompt, there may or may not be 'restrictions.' If there are few/no restrictions, then you have more freedom to TEST values that strike you as easy to work with. The more restrictions there are, the more specific you have to be with the VALUES that you TEST.

Here's another example that doesn't use the LCM....

W/X = 2/3 and W/Y = 8/15

W = 16
X = 24
Y = 30

(X+Y)/Y = (24+30)/30 = 54/30 = 9/5

It still gets us the correct answer.

GMAT assassins aren't born, they're made,
Rich
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Re: If w/x = 2/3 and w/y = 8/15, then (x + y)/y = [#permalink]
EMPOWERgmatRichC wrote:
Hi ak1802,

I didn't have to use the LCM; I chose to TEST VALUES that were the easiest AND fit the 'restrictions' that we were given. In a 'TEST VALUES' prompt, there may or may not be 'restrictions.' If there are few/no restrictions, then you have more freedom to TEST values that strike you as easy to work with. The more restrictions there are, the more specific you have to be with the VALUES that you TEST.

Here's another example that doesn't use the LCM....

W/X = 2/3 and W/Y = 8/15

W = 16
X = 24
Y = 30

(X+Y)/Y = (24+30)/30 = 54/30 = 9/5

It still gets us the correct answer.

GMAT assassins aren't born, they're made,
Rich

All I'm saying is that the value wasn't necessarily being "tested", given the restrictions on it. You found the LCM of X, Y, and Z. If this number was calculated properly, you aren't really "testing" an integer. This integer WILL fit the given rations.

I suppose it's just the semantics of "testing", which I associate some level of uncertainty with. Whereas in this case, there is no uncertainty, as the number both of us used was the LCM.

Don't get me wrong, I am a big supporter of using SMART numbers when "testing" for solutions. However I suppose I just felt that classifying this as testing sounds misleading.
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Re: If w/x = 2/3 and w/y = 8/15, then (x + y)/y = [#permalink]
Bunuel wrote:
If w/x = 2/3 and w/y = 8/15, then (x + y)/y =

A. 4/5
B. 6/5
C. 7/5
D. 8/5
E. 9/5

Kudos for a correct solution.

MAGOOSH OFFICIAL SOLUTION:
Attachment:

wxandy_text.PNG [ 13.86 KiB | Viewed 8288 times ]
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Re: If w/x = 2/3 and w/y = 8/15, then (x + y)/y = [#permalink]
Bunuel wrote:
Bunuel wrote:
If w/x = 2/3 and w/y = 8/15, then (x + y)/y =

A. 4/5
B. 6/5
C. 7/5
D. 8/5
E. 9/5

Kudos for a correct solution.

MAGOOSH OFFICIAL SOLUTION:
Attachment:
wxandy_text.PNG

(x+y)/y = (x/y) +1
so, if we need to get the value of x/y

by dividing w/x by w/y we get the following:

w/x ÷ w/y = w/x *y/w=y/x = 2/3*15/8= 5/4

Therefore x/y=4/5
(x+y)/y= (x/y)+1= 4/5+5/5=9/5 ==> E
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Re: If w/x = 2/3 and w/y = 8/15, then (x + y)/y = [#permalink]
Bunuel wrote:
If w/x = 2/3 and w/y = 8/15, then (x + y)/y =

A. 4/5
B. 6/5
C. 7/5
D. 8/5
E. 9/5

Kudos for a correct solution.

$$\frac{w}{x} = \frac{2}{3}$$ Or, $$\frac{w}{x} = \frac{8}{12}$$

And, $$\frac{w}{y} = \frac{8}{15}$$

So, $$w = 8$$ , $$x = 12$$ & $$y = 15$$

Thus, \frac{(x + y)}{y} = \frac{12 + 15}{15}

= $$\frac{27}{15}$$

= $$\frac{9}{5}$$, answer will be (E)
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Re: If w/x = 2/3 and w/y = 8/15, then (x + y)/y = [#permalink]
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Re: If w/x = 2/3 and w/y = 8/15, then (x + y)/y = [#permalink]
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