BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

defective chips

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

defective chips

by sanju09 » Tue Apr 07, 2009 4:27 am
A computer chip manufacturer expects the ratio of the number of defective chips to the total number of chips in all future shipments to equal the corresponding ratio for shipments S1, S2, S3 and S4 combined, as shown in the following table (read in order). What is the expected number of defective chips in a shipment of 60,000 chips?

Shipment: S1 S2 S3 S4
Number of defective chips in the shipment: 2 5 6 4
Total number of chips in the shipment: 5,000 12,000 18,000 16,000
A. 14
B. 20
C. 22
D. 24
E. 25

OA B
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Top
Source: — Problem Solving |
Senior | Next Rank: 100 Posts
Posts: 92
Joined: Wed Mar 25, 2009 12:13 pm
Thanked: 10 times

by moutar » Tue Apr 07, 2009 4:37 am
Ratio is:

total number of defects:total number of chips (000s)

(2+5+6+4):(5+12+18+16)
= 17:51
= 1:3

So for 60,000 ratio is 20:60 so number of defective chips = 20 B.
Top
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

by sanju09 » Tue Apr 07, 2009 4:53 am
moutar wrote:Ratio is:

total number of defects:total number of chips (000s)

(2+5+6+4):(5+12+18+16)
= 17:51
= 1:3

So for 60,000 ratio is 20:60 so number of defective chips = 20 B.
this explanation doesn't seem to be convincing, moutar; better try again to make it comprehensive to one and all, it's a pre-mature display of some good work by you; leave space between ':' sign and start bracket '(' to avoid :(
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Top
Senior | Next Rank: 100 Posts
Posts: 92
Joined: Wed Mar 25, 2009 12:13 pm
Thanked: 10 times

by moutar » Tue Apr 07, 2009 4:58 am
sanju09 wrote:
this explanation doesn't seem to be convincing, moutar; better try again to make it comprehensive to one and all, it's a pre-mature display of some good work by you; leave space between ':' sign and start bracket '(' to avoid :(
"the ratio of the number of defective chips to the total number of chips in all future shipments to equal the corresponding ratio for shipments S1, S2, S3 and S4 combined"

total number of defects:total number of chips

(2+5+6+4) : (5000+12000+18000+16000)
= 17:51000
= 1:3000

So for 60,000 ratio is 20:60000 so number of defective chips = 20 B.

I don't see what was wrong with the answer I gave before. It was perfectly logical and systematic like I try to make all my answers. Sorry about the smilie. I hate those things.
Top
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

by sanju09 » Tue Apr 07, 2009 5:11 am
nothing was wrong with your answer, it only needed supportive reasoning, like why 1:3 is same as 20:60000 etc..., or may be grammar somewhere, like writing 'defects' for 'defective', not much though :)

why do you hate smilies :wink: ?
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 235
Joined: Wed Oct 26, 2016 9:21 pm
Thanked: 3 times
Followed by:5 members

by Anaira Mitch » Sat Jan 14, 2017 12:59 pm
(2+5+6+4)/(5000+12000+18000+16000)*60000 = 20
Answer is B
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Sat Jan 14, 2017 1:57 pm
Shipment / Number of Defective Chips in the Shipment / Total number of Chips in the Shipment
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 number of defective chips to the total number of chips in all the future shipments to equal the corresponding rate for shipments S1, S2, S3, and S4 combined, as shown in the table above. What is the expected number of defective chips in the shipment of 60,000 chips?

A) 14

B) 20

C) 22

D) 24

E) 25
Let's find some TOTALS for all 4 shipments combined.
There are 51,000 chips altogether
There are 17 defective chips altogether.

So, 17/51000 of the chips are defective. (notice that 17 divides nicely into 51000!)
SIMPLIFY: 1/3000 of the chips are defective

So, if we have a shipment of 60,000 chips, 1/3000 of them will be defective.
(1/3000)(60,000) = 20 defective chips

Answer: B

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 8088
Joined: Sat Apr 25, 2015 10:56 am
Location: Los Angeles, CA
Thanked: 43 times
Followed by:29 members

by Scott@TargetTestPrep » Thu Jan 19, 2017 4:46 pm
sanju09 wrote:A computer chip manufacturer expects the ratio of the number of defective chips to the total number of chips in all future shipments to equal the corresponding ratio for shipments S1, S2, S3 and S4 combined, as shown in the following table (read in order). What is the expected number of defective chips in a shipment of 60,000 chips?

Shipment: S1 S2 S3 S4
Number of defective chips in the shipment: 2 5 6 4
Total number of chips in the shipment: 5,000 12,000 18,000 16,000
A. 14
B. 20
C. 22
D. 24
E. 25

We are given the following:

S1: 2 defective chips out of 5,000 total

S2: 5 defective chips out of 12,000 total

S3: 6 defective chips out of 18,000 total

S4: 4 defective chips out of 16,000 total

The ratio of the number of defective chips to total chips is:

(2 + 5 + 6 + 4)/(5,000 + 12,000 + 18,000 + 16,000)

17/51,000 = 1/3,000

We see that we would expect 1 chip out of every 3,000 chips to be defective.

We can set up a proportion to determine the number of defective chips that we would expect in a 60,000 shipment of chips.

1/3,000 = x/60,000

60,000 = 3,000x

x = 20 chips

Answer: B

Scott Woodbury-Stewart
Founder and CEO
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

ImageImage
Top
GMAT Instructor
Posts: 2630
Joined: Wed Sep 12, 2012 3:32 pm
Location: East Bay all the way
Thanked: 625 times
Followed by:119 members
GMAT Score:780

by Matt@VeritasPrep » Thu Jan 19, 2017 6:42 pm
This one seems below average difficulty for the modern GMAT, so be wary of that if you're using it today. (It was probably an average-ish difficulty question in 2009 when it was first posted, though.)
Top
Post new topic Post Reply
• Page 1 of 1