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

Question

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

Kudos for a correct  solution .

EMPOWERgmatRichC · Accepted Answer

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

Final Answer:  E

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

ak1802 · Answer

Ratio 1:

3w = 2x
multiple of 5:
15w = 10x

Ratio 2:

15w = 8y

LCM of 8, 15, 10 = 120.

Ratio 1 : 15(8) = 10(12) 
therefore x = 12

Ratio 2 : 15(8) = 8(15)
therefore y = 15

(15+12)/15 is reduced to 9/5.

Answer E. 9/5

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OptimusPrepJanielle · Answer

We need (x+y)/y = x/y + 1 Now, w/x = 2/3 => x = (3w)/2 Also, w/y = 8/15 => y = (15w)/8 We need x/y + 1 = (3w/2) / (15w/8) + 1 = (3w/2) * (8/15w) + 1 = 4/5 + 1 = 9/5 Hence option E. -- Optimus Prep's GMAT On Demand course for only $299 covers all verbal and quant. concepts in detail. Visit the following link to get your 7 days free trial account: https://www.optimus-prep.com/gmat-on-demand-course

ak1802 · Answer

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.

EMPOWERgmatRichC · Answer

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

ak1802 · Answer

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.

Bunuel · Answer

MAGOOSH OFFICIAL SOLUTION: wxandy_text.PNG

NDND · Answer

Correct Answer: E
(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

Abhishek009 · Answer

\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)

sompant_98 · Answer

Here we have w/x =2/3 and w/y= 8/15
now w has two different values, we need to multiply w/x with 8 and w/y with 2 so that value w becomes equal

In doing so we get w/x= 16/24 and w/y= 16/30. Therefore w : x : y= 16:24:30

Therefore, (x+y)/y= (24+30)/30= 9/5

alamin8 · Answer

Here is a different way probably:
w/x = 2/3 = 2*4/3*4 = 8/12
w/y = 8/15

x/y = 12/15
(x + y)/y = 27/15 = 9/5
Answer: E

KeenBoar · Answer

Easiest way:

Take reciprocal of any 1 fraction to remove w. 
Hence,

(w/x ) * (y/w) = y/x = 5/4
=> (x + y)/ y = (4 + 5) /5 = 9/5

Answer choice E

alamin8 · Answer

Here he goes! More efficient way. 
Processed correctly and it is really a smart way to do faster.

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

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