Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 20 Oct 2016, 17:33

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# A computer chip manufacturer expects the ratio of the number

Author Message
TAGS:

### Hide Tags

Manager
Joined: 13 Mar 2006
Posts: 74
Followers: 1

Kudos [?]: 33 [0], given: 0

A computer chip manufacturer expects the ratio of the number [#permalink]

### Show Tags

19 Mar 2006, 03:36
1
This post was
BOOKMARKED
00:00

Difficulty:

45% (medium)

Question Stats:

68% (02:01) correct 32% (01:39) wrong based on 82 sessions

### HideShow timer Statistics

Shipment ------No. of Defective Chips/shipment---Total Chips in shipment
S1 -------------- 2 -----------------------------------------------5000
S2 -------------- 5 ------------------------ ----------------------12000
S3 -------------- 6 ----------------------------------------------- 18000
S4 -------------- 4 ----------------------------------------------- 16000

A computer chip manufacturer expects the ratio of the number of defective chips to be total number of chips in all future shipments equal to the corresponding ratio for shipmemts S1,S2,S3 and S4 comined as shown in the table above. What is the expected number of defective chips in a shipment of 60000 chips?

A. 14
B. 20
C. 22
D. 24
E. 25

OPEN DISCUSSION OF THIS QUESTION IS HERE: a-computer-chip-manufacturer-expects-the-ratio-of-the-number-126050.html
[Reveal] Spoiler: OA

_________________

GMAT by 8th JUL

Last edited by Bunuel on 06 May 2012, 02:47, edited 1 time in total.
Edited the question. Topic locked.
Manager
Joined: 12 Feb 2006
Posts: 71
Followers: 1

Kudos [?]: 3 [1] , given: 0

Re: PS from OG 11th [#permalink]

### Show Tags

19 Mar 2006, 08:09
1
KUDOS
1
This post was
BOOKMARKED
foolbox wrote:
shipment, # of defective chips, total # of chips
S1 2 5,000
S2 5 12,000
S3 6 18,000
S4 4 16,000

A computer chip manufacturer expects the ratio of the # of defective chips to the total # of chips in all future shipments to equal the corresponding ratio for shipments S1,S2,S3, and S4 combined, as shown in the table above. What is the expected number of defective chips in a shipment of 60,000 chips?

Say X is the number of defective ships in the shipment of 60,000

we can write out the following equation

2+5+6+4/5,000+12,000+18,000+16,000 = X/60,000

17/51,000 = X/60,000

51,000X= 1,020,000
X= 20
_________________

The greater the sacrifice, the greater the Victory

GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5062
Location: Singapore
Followers: 30

Kudos [?]: 336 [0], given: 0

### Show Tags

19 Mar 2006, 08:10
Total # of defective chips =17
Total # of chips = 51000

# of defective chips in a shipment of 60,000 chips
= (60,000/51,000) * 17
= (60/51) * 17
= (20/17) * 17
= 20
Manager
Joined: 13 Mar 2006
Posts: 74
Followers: 1

Kudos [?]: 33 [0], given: 0

Re: PS from OG 11th [#permalink]

### Show Tags

19 Mar 2006, 09:38
foolbox wrote:
shipment, # of defective chips, total # of chips
S1 2 5,000
S2 5 12,000
S3 6 18,000
S4 4 16,000

A computer chip manufacturer expects the ratio of the # of defective chips to the total # of chips in all future shipments to equal the corresponding ratio for shipments S1,S2,S3, and S4 combined, as shown in the table above. What is the expected number of defective chips in a shipment of 60,000 chips?

How come we can't solve this problem like;

Viewing package S1, and using proportional

2:5,000 = X:60,000

X = 60,000 * 2 / 5,000 = 24

Doesn't that make sense, guys?

_________________

GMAT by 8th JUL

Manager
Joined: 12 Feb 2006
Posts: 71
Followers: 1

Kudos [?]: 3 [0], given: 0

Re: PS from OG 11th [#permalink]

### Show Tags

19 Mar 2006, 09:44
foolbox wrote:
foolbox wrote:
shipment, # of defective chips, total # of chips
S1 2 5,000
S2 5 12,000
S3 6 18,000
S4 4 16,000

A computer chip manufacturer expects the ratio of the # of defective chips to the total # of chips in all future shipments to equal the corresponding ratio for shipments S1,S2,S3, and S4 combined, as shown in the table above. What is the expected number of defective chips in a shipment of 60,000 chips?

How come we can't solve this problem like;

Viewing package S1, and using proportional

2:5,000 = X:60,000

X = 60,000 * 2 / 5,000 = 24

Doesn't that make sense, guys?

We can't just take one shipment and make and equation since the stem explicitly states .." in all future shipments to equal the corresponding ratio for shipments S1,S2,S3, and S4 combined".

So you must have all the values in the equation
_________________

The greater the sacrifice, the greater the Victory

Intern
Joined: 09 Jun 2005
Posts: 32
Followers: 0

Kudos [?]: 0 [0], given: 0

### Show Tags

20 Mar 2006, 14:35
The generic formula for such type of ratio problems is

Part1/Part2 = New Part1/Whole

In this problem it will be

Total defective Chips/Total Chips from all shipments = X / 60000

which will be

17/51000 = x/60000
Hence, X=20
Intern
Joined: 25 Feb 2008
Posts: 16
Followers: 0

Kudos [?]: 1 [0], given: 0

Re: PS from OG 11th [#permalink]

### Show Tags

20 Mar 2008, 08:47
Why dont you have to find a common denominator before adding up the ratios? I feel like I am overlookng something easy and fundamental.

Manager
Joined: 31 Oct 2007
Posts: 113
Location: Frankfurt, Germany
Followers: 2

Kudos [?]: 57 [0], given: 0

Re: PS from OG 11th [#permalink]

### Show Tags

20 Mar 2008, 08:59
foolbox wrote:
shipment, # of defective chips, total # of chips
S1 2 5,000
S2 5 12,000
S3 6 18,000
S4 4 16,000

A computer chip manufacturer expects the ratio of the # of defective chips to the total # of chips in all future shipments to equal the corresponding ratio for shipments S1,S2,S3, and S4 combined, as shown in the table above. What is the expected number of defective chips in a shipment of 60,000 chips?

The key phrase in this question is "expects the ratio of the # of defective chips to the total # of chips in all future shipments to equal the corresponding ratio for shipments S1,S2,S3, and S4 combined".

To rephrase the sentense, if there are 17 defects to 51,000 chips, what is the proportion of defect for 60,000 chips?
=> 60,000 / 51,000 * 17 = ~ 20 (19.9999)
_________________

Jimmy Low, Frankfurt, Germany
Blog: http://mytrainmaster.wordpress.com
GMAT Malaysia: http://gmatmalaysia.blogspot.com

Intern
Joined: 26 Mar 2010
Posts: 48
Followers: 0

Kudos [?]: 8 [3] , given: 5

### Show Tags

25 Oct 2010, 08:04
3
KUDOS
Summing all the defective chips in the table gives you 2 + 5 + 6 + 4 = 17.
Summing all the total number of chips in each shipment gives you 5k + 12k + 18k + 16k = 51k.

Then, setting up a ratio can help you solve the problem. Since you know there's 17 defective chips in a shipment of 51k, set that equal to x/60k and solve.

17/51k = x/60k
17/51k = 1/3k
1/3k = x/60k
60k/3k = x
x = 20
Intern
Joined: 08 Sep 2010
Posts: 4
Followers: 0

Kudos [?]: 0 [0], given: 7

### Show Tags

30 Oct 2010, 01:23
I agree with your solution = 20. But the question is:

There are different combination to get 60,000 chips. For example: 1*S3 + 2*S4 + 2*S2. In this way, we ship 60,000 chips with only 6 + 4*2 + 2*2 = 18 defective chips, better than the average of 20.

The question is to find the expected number of defective chips, i guess it assume the minimum #, therefore it might not be 20.

Or i misunderstand the word "EXPECT"
Manager
Joined: 25 Jun 2010
Posts: 91
Followers: 1

Kudos [?]: 32 [0], given: 0

Re: Practice Test 2 Q1 [#permalink]

### Show Tags

31 Dec 2010, 20:10
There are (2+5+6+4 = 17) defective pieces in shipment of (5000+12000+18000+16000=51000) pieces.
That is equivalent to 1 defective piece/3000 shipment of pieces.

So, in a shipment of 60000 pieces, there will be (1/3000) * 60000 = 20 defective pieces.
Manager
Status: Never give up!
Affiliations: Beta Gamma Sigma, Omicron Delta Epsilon, Toastmasters Intl, HHonors
Joined: 04 Nov 2009
Posts: 223
Location: Raleigh-Durham NC
Followers: 3

Kudos [?]: 47 [1] , given: 27

### Show Tags

04 May 2011, 12:22
1
KUDOS

1) Sum of chips in all shipments: 51,000
2) Sum of defects in all shipments: 17
3) So, defects:chips is 1:3000

As such, 60,000 chips x (1 defect / 3000 chips) = 20 defects

If there's any hole in my reasoning, I welcome comments. As I can benefit from it too.
_________________

= = = = = = = = = =

If you liked my post, please consider a Kudos for me. Thanks!

Director
Joined: 01 Feb 2011
Posts: 757
Followers: 14

Kudos [?]: 108 [0], given: 42

### Show Tags

04 May 2011, 17:40
x/60000 = (2+5+6+4)/51000

=> x = (17/51000)*60000

= 20

SVP
Joined: 16 Nov 2010
Posts: 1673
Location: United States (IN)
Concentration: Strategy, Technology
Followers: 34

Kudos [?]: 491 [0], given: 36

### Show Tags

05 May 2011, 07:41
Ratio = 17/510000 (adding the respective columns)

17/51000 = x/60000

=> x = 20

_________________

Formula of Life -> Achievement/Potential = k * Happiness (where k is a constant)

GMAT Club Premium Membership - big benefits and savings

Manager
Joined: 28 May 2011
Posts: 195
Location: United States
GMAT 1: 720 Q49 V38
GPA: 3.6
WE: Project Management (Computer Software)
Followers: 2

Kudos [?]: 57 [0], given: 7

Re: problem solving questions..GMAT Prep [#permalink]

### Show Tags

15 Aug 2011, 07:04
key is to understand the meaning of "corresponding ratio for shipments S1, S2, S3, S4 combined"

first I thought it (considering r as the ratio) is equal to = r1+r2+r3+r4, however that gave me answer 84.

So correct interpretation is (take d as nbr of defective and t as nbr of total artifacts ), it is equal to = (d1+d2+d3+d4)/(t1+t2+t3+t4)

so the combined ration comes = 17/51000 = 1/3000

and nbr of defective in a shipment of 60,000 = 60,000 * 1/3000 = 20

_________________

-------------------------------------------------------------------------------------------------------------------------------
http://gmatclub.com/forum/a-guide-to-the-official-guide-13-for-gmat-review-134210.html
-------------------------------------------------------------------------------------------------------------------------------

Manager
Joined: 12 Feb 2012
Posts: 136
Followers: 1

Kudos [?]: 48 [0], given: 28

Re: A computer chip manufacturer [#permalink]

### Show Tags

05 May 2012, 08:46
This question is total bullocks. Everyone here took a simple arithmetic average (Total number of Defective)/(Total number of all shipments). I took a weighted average. Obviously the larger shipments should get more weight. Does anyone agree the wording of this question is awkward?
Math Expert
Joined: 02 Sep 2009
Posts: 35220
Followers: 6615

Kudos [?]: 85241 [0], given: 10231

Re: A computer chip manufacturer [#permalink]

### Show Tags

06 May 2012, 02:48
alphabeta1234 wrote:
This question is total bullocks. Everyone here took a simple arithmetic average (Total number of Defective)/(Total number of all shipments). I took a weighted average. Obviously the larger shipments should get more weight. Does anyone agree the wording of this question is awkward?

There is nothing wrong with the question or the solutions.

Shipment ------No. of Defective Chips/shipment---Total Chips in shipment
S1 -------------- 2 -----------------------------------------------5000
S2 -------------- 5 ------------------------ ----------------------12000
S3 -------------- 6 ----------------------------------------------- 18000
S4 -------------- 4 ----------------------------------------------- 16000

A computer chip manufacturer expects the ratio of the number of defective chips to be total number of chips in all future shipments equal to the corresponding ratio for shipmemts S1,S2,S3 and S4 comined as shown in the table above. What is the expected number of defective chips in a shipment of 60000 chips?

A. 14
B. 20
C. 22
D. 24
E. 25

Set up equation: $$\frac{x}{60,000}=\frac{2+5+6+4}{5,000+12,000+18,000+16,000}$$ --> $$x=20$$;

Or: $$2+5+6+4=17$$ defective chips in $$5,000+12,000+18,000+16,000=51,000$$ chips, so $$\frac{17}{51,000}=\frac{1}{3,000}$$: 1 in 3,000. So, expected number of defective chips in a shipment of 60,000 chips is $$\frac{60,000}{3,000}=20$$.

OPEN DISCUSSION OF THIS QUESTION IS HERE: a-computer-chip-manufacturer-expects-the-ratio-of-the-number-126050.html
_________________
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 12132
Followers: 538

Kudos [?]: 151 [0], given: 0

Re: A computer chip manufacturer expects the ratio of the number [#permalink]

### Show Tags

12 Oct 2016, 04:06
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Re: A computer chip manufacturer expects the ratio of the number   [#permalink] 12 Oct 2016, 04:06
Similar topics Replies Last post
Similar
Topics:
1 Irin, Ingrid and Nell bake chocolate chip cookies in the ratio of 9.18 7 29 Jun 2016, 07:52
3 A computer manufacturer claims that a perfectly square computer 4 28 Feb 2016, 01:03
3 A computer manufacturer produces a certain electronic component at a c 4 05 Feb 2015, 09:04
29 A computer chip manufacturer expects the ratio of the number 14 25 Oct 2010, 07:40
7 A computer chip manufacturer expects the ratio of the number of defect 4 26 Feb 2009, 22:30
Display posts from previous: Sort by