A basic quant question

[sankruth]

If the problem states "...difference between A and B is 10", then should we always consider this as A - B = 10 or could it also mean B - A = 10?

[gmatguy16]

it could mean either way

[sankruth]

I too thought the same but came across a DS problem in GMAT Quant Review book where the official solution uses A - B.

In this problem if interpret st#2 as B - A the answer will be different...

The perimeter of a rectangular garden is 360 feet. What is the length of the garden?

1. The length of the garden is twice the width

2. The difference between length and width of the garden is 60 feet.

[Tud]

That's interesting. Statement 1 is sufficient, but statement 2 will depend on how you interpret "difference". The official answer would tell us how they interpret it, so....., what's the OA?

[sankruth]

The OA is D

St 2 is intrpreted as (l - w) only!

[Tud]

The OA is D

St 2 is intrpreted as (l - w) only!

That's good to know, so we can assume that when they say the difference of a and b they mean a-b only.

[Argen]

I think by definition, the length of a rectangle is the longer side and the width shorter side.

[II]

I think by definition, the length of a rectangle is the longer side and the width shorter side.

Good point !

[sankruth]

Thanks! That makes it very clear!

[camitava]

Guys a long discussion it was! But I am not getting one point and also I would like to express my view -
Guys this is a Qs from DS. Our aim should be to find out whether the ways the options are mentioning can take us to the conclusion. Now going back to ur Qs sankruth -

The perimeter of a rectangular garden is 360 feet. What is the length of the garden?

1. The length of the garden is twice the width

2. The difference between length and width of the garden is 60 feet.

If we go with 1, we can get the value of l and w.
Again if we go with 2, l - w =60
2(l + w) = 360 or l + w = 180 - By these two equ, we can get the value of l and w.
If you take option - 2 as w - l = 60 then also u can get the value of w and l.
It can happen that the values we are getting may not match with the answer directed by other option.
But bottom-line is we can get the value of length by the two options specified. So D is fine!
I am not getting where I missed! Please let me know if I am wrong anyhow.

[sankruth]

camitava,
Length is always the longer dimension and this is as defined in the dictionary. This assumption is key to interpreting st#2

Anyway, if one goes with the interpretion of st#2 as (w - l), then one must also consider the interpretation, (l - w). Each interpretaion will give a different value for l, thus making st#2 INSUFF.

Hope that helps!