Hi

Please provide a suitable explanation for the question.The answer for the same is statement 2 alone is sufficient.

Question:
In the figure (attached), what is the ratio KN/MN?
1. The perimeter of rectangle KLMN is 30 meters.
2. The 3 small rectangles have the same dimensions.


Thanks
Upinder

Hi, Upinder

Can you please post the source for your question? The author / company's name and, if appropriate, the name of the book and question number.

Thanks!
Stacey

The sorce is gmatprep, i got this question today.

(1)
definitely not sufficient, as the outer dimensions can be any length and width that add up to 15 (which would then give a perimeter of 30).

(2)
let the longer dimension of each small rectangle = L and the shorter dimension = W.
then
2W = L (look at the horizontal line in the middle of the rectangle :: one side of it is covered by two W's, the other side by one L, and both are the same length in total)
4W + 3L = 30 (add up all the pieces of the perimeter; the whole perimeter is 30)
if we substitute, as is routine for simultaneous equations, we arrive at
4W + 3(2W) = 30
this can be solved
SUFFICIENT (remember that you don't have to solve it!)

answer = b

Hey Ron can you explain why you only used 2 of the smaller triangles (4w+3L=30) in the equation rather than using all three of the smaller triangles (6w+4L=30)???

Thanks

because 30 is the perimeter of the figure; the perimeter comprises only those segments that are actually part of the figure's boundary.

think about it: you can draw all kinds of other lines through the interior of the figure if you really feel like it; clearly none of those lines will have any effect upon the perimeter of the figure. only the 4 w's and 3 l's around the outside of the large rectangle count.

make sense?

Sorry in my last post i wrote tirangles but really meant to say rectangles... duhhh...
Anyway I do understand your point, I appreciate the great clarification!
However I do have another concern: isn't assuming the perimeter = 30 a statement carryover from statement 1?
Also do you think you can speculate on what level question this would be.... Thanks

Hmm, yes, what you definitely want to notice is that 2W=L, as Ron says above. And then I'm noticing that his first post was at 2:43a, so perhaps he was a little tired... :)

I want to know the ratio of KN to MN. If I know a relationship between the length and the width, I can write KN and MN in terms of just L or just W. Eg, KN = 2W and MN = 3W

So KN/MN = 2W/3W = 2/3. Sufficient. Good catch, KT!