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SVP  Joined: 24 Aug 2006
Posts: 2040
The ratio by weight, measured in pounds, of books to clothes  [#permalink]

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2
29 00:00

Difficulty:   75% (hard)

Question Stats: 60% (02:30) correct 40% (02:40) wrong based on 556 sessions

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The ratio by weight, measured in pounds, of books to clothes to electronics in Jorge's suitcase initially stands at 8 to 5 to 3. Jorge then removes 4 pounds of clothing from his suitcase, thereby doubling the ratio of books to clothes. Approximately how much do the electronics in the suitcase weigh, to the nearest pound?

A. 3
B. 4
C. 5
D. 6
E. 7

Originally posted by kidderek on 08 Nov 2006, 20:37.
Last edited by Bunuel on 12 Aug 2014, 01:19, edited 1 time in total.
Renamed the topic, edited the question, added the OA and moved to PS forum.
Manager  Joined: 03 Jan 2015
Posts: 72
Re: The ratio by weight, measured in pounds, of books to clothes  [#permalink]

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8
3
Given =

$$B : C : E$$
$$8 : 5 : 3$$

$$\frac{8x}{5x-4}$$ = $$\frac{16}{5}$$ ---> $$8x(5) = 16(5x - 4)$$ ---> $$40x = 80x - 64$$ ---> $$-40x = -64$$ ---> $$x = 1.6$$

$$1.6 * 3 = 4.8$$

General Discussion
Manager  Joined: 01 Oct 2006
Posts: 202
Re: The ratio by weight, measured in pounds, of books to clothes  [#permalink]

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1
1
I also go for C. Electronics weigh 4.8 pounds, approx 5
Director  Joined: 06 Feb 2006
Posts: 711
Re: The ratio by weight, measured in pounds, of books to clothes  [#permalink]

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I am also getting C... however look at my calculations, why i am getting this?

b+c+e=16

b/c=8/5..... (1)
b/c-4=16/5.....(2)

From (1)
5b=8c
b=8/5c....include this in (2)

From (2)
5b=16c-64....include b from (1)
8c=16c-64
-8c=-64
c=8

If c=8, then b is
b/8=8/5
5b=64
b=12,8

12.8+8+e=16
20.8+e=16
e=-4.8..... why i'am getting this?
CEO  Joined: 07 Jul 2004
Posts: 3793
Location: Singapore
Re: The ratio by weight, measured in pounds, of books to clothes  [#permalink]

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3
4
Ratio
B:C:E = 8:5:3

Total weight of items = x

Weight of books = 8x/16
Weight of clothes = 5x/16
Wegith of electronics = 3x/16

New total weight of items = (x-4)
Weight of clothes = 5x/16 - 4 = (5x-64)/16

New Ratio B:C:E =
8x/16(x-4) : (5x-64)/16(x-4) : 3x/16(x-4)
8x : 5x-64 : 3x

We're told B:C = 16:5
So B/C = 16/5 = 8x/5x-64
80x - 1024 = 40x
40x = 1025
x = 25.6

Electronics = 3x/16 = 4.8 pounds ~ 5 pounds
SVP  Joined: 24 Aug 2006
Posts: 2040
Re: The ratio by weight, measured in pounds, of books to clothes  [#permalink]

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1
ywilfred wrote:
Ratio
B:C:E = 8:5:3

Total weight of items = x

Weight of books = 8x/16
Weight of clothes = 5x/16
Wegith of electronics = 3x/16

New total weight of items = (x-4)
Weight of clothes = 5x/16 - 4 = (5x-64)/16

New Ratio B:C:E =
8x/16(x-4) : (5x-64)/16(x-4) : 3x/16(x-4)
8x : 5x-64 : 3x

We're told B:C = 16:5
So B/C = 16/5 = 8x/5x-64
80x - 1024 = 40x
40x = 1025
x = 25.6

Electronics = 3x/16 = 4.8 pounds ~ 5 pounds

Maybe I'm misunderstanding the question, but if the weights of the B:C:E is 12.8 : 8 : 4.8, and you take four pounds of clothes away, aren't you left with 12.8 : 4 : 4.8? But 12.8 is more than double 4.
Manager  Joined: 03 Nov 2006
Posts: 146
Re: The ratio by weight, measured in pounds, of books to clothes  [#permalink]

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By removing the 4 pounds, you're doubling the original ratio - not making B double C. So the new ratio is 16/5
SVP  Joined: 24 Aug 2006
Posts: 2040
Re: The ratio by weight, measured in pounds, of books to clothes  [#permalink]

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1
hosam wrote:
By removing the 4 pounds, you're doubling the original ratio - not making B double C. So the new ratio is 16/5

thank you.

i gotta be more careful in reading these problems.
Senior Manager  Joined: 11 Dec 2008
Posts: 419
Location: United States
GMAT 1: 760 Q49 V44 GPA: 3.9
Ambiguous interpretation... possible in real GMAT?  [#permalink]

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3
I was wondering if anyone else experienced confusion during the question. Take this example from MGMAT:

The ratio by weight, measured in pounds, of books to clothes to electronics in Jorge's suitcase initially stands at 8 to 5 to 3. Jorge then removes 4 pounds of clothing from his suitcase, thereby doubling the ratio of books to clothes. Approximately how much do the electronics in the suitcase weigh, to the nearest pound?

a) 3
b) 4
c) 5
d) 6
e) 7

When I hear, thereby "doubling" the ratio of books to clothes, I think that the book to clothes ratio become 2:1, which is colloquial but not correct.

Initially the ratio of B: C: E can be written as 8x: 5x: 3x. (Recall that ratios always employ a common multiplier to calculate the actual numbers.)
After removing 4 pounds of clothing, the ratio of books to clothes is doubled. To double a ratio, we double just the first number; in this case, doubling 8 to 5 yields a new ratio of 16 to 5. This can be expressed as follows:

8x/5x – 4 = 16/5.
Cross multiply to solve for x:
40x = 80x – 64
40x = 64
x = 8/5
The question asks for the approximate weight of the electronics in the suitcase. Since there are 3x pounds of electronics there are 3 × (8/5) = 24/5 or approximately 5 pounds of electronics in the suitcase.
The correct answer is C.

However, I did 8x/5x – 4 = 2. => choice d)

I see how they mean "double" due to the technicalities of the english sentence but I would be really ticked off if this appeared on an actual GMAT. Is this MGMAT's lack of clarity or will the real GMAT use this tricky language?
GMAT Tutor G
Joined: 24 Jun 2008
Posts: 1806
Re: Ambiguous interpretation... possible in real GMAT?  [#permalink]

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bipolarbear wrote:
The ratio by weight, measured in pounds, of books to clothes to electronics in Jorge's suitcase initially stands at 8 to 5 to 3. Jorge then removes 4 pounds of clothing from his suitcase, thereby doubling the ratio of books to clothes. Approximately how much do the electronics in the suitcase weigh, to the nearest pound?

There are quite a few details of the wording here which make it unlike a real GMAT question. The ratio in the question is unitless (it's the same ratio whether you measure the weights in nanograms, pounds or tons), so the phrase 'measured in pounds' is redundant and misleading. The phrase 'stands at' is a colloquialism, and not something that would appear in a real test question. When the question says Jorge's action doubles 'the ratio of books to clothes', that phrase is also misleading. The intended meaning is that it doubles 'the ratio of the weight of the books to the weight of the clothes'. One could easily think the statement was referring to the number of books, for example, and not their weight. No real GMAT question is ever so imprecise with its wording.

However, I don't have an issue with the phrase 'doubling the ratio'; ratios are fractions, so if you double a ratio, you're multiplying the first part of the ratio -- the numerator -- by 2.
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Manager  Joined: 03 Jul 2009
Posts: 96
Location: Brazil
Re: Ambiguous interpretation... possible in real GMAT?  [#permalink]

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bipolarbear, If you have a question like that on Real GMAT, ask for IanStewart write for GMAC to cancel the question.....hehe

This explanation gave me hope. When I read the question I had the same impression: What exactly the question mean?
Manager  Joined: 27 Jun 2008
Posts: 119
Re: Ambiguous interpretation... possible in real GMAT?  [#permalink]

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Think that doubling ratio has a fairly straight forward meaning i.e. X:Y to double would result in 2X:Y
Intern  B
Joined: 24 Sep 2016
Posts: 4
Re: The ratio by weight, measured in pounds, of books to clothes  [#permalink]

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B:C:E=8:5:3

B=8x & C=5x C'=C-4=5x-4

B:C'=8x/(5x-4)=2*8/5

40x=80x-64
=>36x=64
=>x=16/9

E=3 * 16/9 =5.33 ~~ 5 (C)
Intern  B
Joined: 14 May 2015
Posts: 47
Re: The ratio by weight, measured in pounds, of books to clothes  [#permalink]

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8x/(5x-4)=16/5
x=64/40
electronics=64/40*3=5(ans)
Manager  B
Joined: 19 Aug 2015
Posts: 84
Location: India
GMAT 1: 650 Q49 V30 Re: The ratio by weight, measured in pounds, of books to clothes  [#permalink]

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Ration of weights B:C:E = 8:5:3
Then weight of Book, Clothes and Electronics be 8a,5a,3a respectively.
After removing 4pounds from clothes B:C become 2*8:5
This gives, 8a/(5a-4) = 2*8/5
a = 1.6
So weight of electronics = 3*1.6 = 4.8 ~ 5
Intern  Joined: 28 Jun 2017
Posts: 1
Re: The ratio by weight, measured in pounds, of books to clothes  [#permalink]

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ywilfred wrote:
Ratio
B:C:E = 8:5:3

Total weight of items = x

Weight of books = 8x/16
Weight of clothes = 5x/16
Wegith of electronics = 3x/16

New total weight of items = (x-4)
Weight of clothes = 5x/16 - 4 = (5x-64)/16

New Ratio B:C:E =
8x/16(x-4) : (5x-64)/16(x-4) : 3x/16(x-4)
8x : 5x-64 : 3x

We're told B:C = 16:5
So B/C = 16/5 = 8x/5x-64
80x - 1024 = 40x
40x = 1025
x = 25.6

Electronics = 3x/16 = 4.8 pounds ~ 5 pounds

Could just be that it is a very long day, but can someone please explain how upon doubling 8x/5x-4, it becomes 16/5? I can't get past this step.
Manager  G
Joined: 27 Jan 2016
Posts: 123
Schools: ISB '18
GMAT 1: 700 Q50 V34 Re: The ratio by weight, measured in pounds, of books to clothes  [#permalink]

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kidderek wrote:
The ratio by weight, measured in pounds, of books to clothes to electronics in Jorge's suitcase initially stands at 8 to 5 to 3. Jorge then removes 4 pounds of clothing from his suitcase, thereby doubling the ratio of books to clothes. Approximately how much do the electronics in the suitcase weigh, to the nearest pound?

A. 3
B. 4
C. 5
D. 6
E. 7

B/C = 8/5
So 5B=8C -----Eqn1

B/C-4 = 16/5
So 5B=16C-64----Eqn2

Solving Eqn 1 & 2
8C=16C-64
So C=8

C/E=5/3
8/E=5/3
E=24/5 = 5
Target Test Prep Representative G
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
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Re: The ratio by weight, measured in pounds, of books to clothes  [#permalink]

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kidderek wrote:
The ratio by weight, measured in pounds, of books to clothes to electronics in Jorge's suitcase initially stands at 8 to 5 to 3. Jorge then removes 4 pounds of clothing from his suitcase, thereby doubling the ratio of books to clothes. Approximately how much do the electronics in the suitcase weigh, to the nearest pound?

A. 3
B. 4
C. 5
D. 6
E. 7

We are given that the ratio of books to clothes to electronics = 8x : 5x : 3x. We are also given that Jorge removes 4 pounds of clothing from his suitcase, thereby doubling the ratio of books to clothes, from 8/5 to (2)(8)/5. Thus:

2(8)/5 = 8x/(5x - 4)

16(5x - 4) = 40x

80x - 64 = 40x

40x = 64

x = 64/40 = 1.6

Thus, we see the electronics weigh 3 x 1.6 = 4.8 or about 5 pounds.

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Re: The ratio by weight, measured in pounds, of books to clothes  [#permalink]

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_________________ Re: The ratio by weight, measured in pounds, of books to clothes   [#permalink] 06 Oct 2018, 11:39
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