Work Rate DS Problem

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Bens4vcobra: Senior | Next Rank: 100 Posts; Posts: 76; Joined: Thu Feb 19, 2009 12:10 pmFollowed by: 2 members; Thanked: 3 times

by Bens4vcobra » Mon Jun 20, 2011 4:14 pm

To fill an order on schedule, a manufacturer had to produce 1000 tools per day for N days, what is the value of N?

1) Because of production problems, the manufacturer only produced 600 tools for the first 5 days
2) Because of production problems, the manufacturer had to produce 1500 tools per day for each of the last 4 days to meet the schedule

"It takes no ability to give effort. Toughness is not God-given; it's a choice. The discipline to execute is a habit." - Nick Saban

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Source: Beat The GMAT — Data Sufficiency | Mon Jun 20, 2011 4:14 pm

ChrisK: Newbie | Next Rank: 10 Posts; Posts: 3; Joined: Fri Oct 22, 2010 2:08 am

by ChrisK » Mon Jun 20, 2011 10:01 pm

Hi, IMHO:

This is a work rate problem. Upfront, we have:

Rate = 1000/day
Time = N days
Job = 1000N

Therefore, in order to get the value of N, we need to know the value of the job.

Statement #1 - This tells us that the manufacturer has produced only 600 tools over the first five days, but tells us nothing about how many more days the manufacturer will be producing tools.

State#2 - This tells us that over the last 4 days, the manufacturer produced 1500 tools/day (6,000 total) but does not tell us how many days of production problems the manufacturer had.

Neither of the statements individually tell us enough to answer the question.

Let's look at them together.

Statement #1 tells us that we have 600 tools after 5 days. Statement #2 tells us that the job is done once 6,000 more tools are produced. Taken together, this tells us that the job is for 6,600 tools total.

Going back to the original question;
Job = rate X time
6,600 = 1,000 X N
N = 6.6 days

Therefore, the answer is [spoiler]'C'[/spoiler]

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Frankenstein: Legendary Member; Posts: 1448; Joined: Tue May 17, 2011 9:55 amFollowed by: 53 members; Location: India; Thanked: 375 times

by Frankenstein » Mon Jun 20, 2011 10:04 pm

Bens4vcobra wrote: 1) Because of production problems, the manufacturer only produced 600 tools for the first 5 days

Hi,
Can you check statement(1) again. Is it 600tools per day for the first 5 days? Please check for errors while posting the question.

Cheers!

Things are not what they appear to be... nor are they otherwise

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Geva@EconomistGMAT: GMAT Instructor; Posts: 905; Joined: Sun Sep 12, 2010 1:38 amFollowed by: 123 members; Thanked: 378 times; GMAT Score:760

by Geva@EconomistGMAT » Mon Jun 20, 2011 10:13 pm

Bens4vcobra wrote:To fill an order on schedule, a manufacturer had to produce 1000 tools per day for N days, what is the value of N?

1) Because of production problems, the manufacturer only produced 600 tools for the first 5 days
2) Because of production problems, the manufacturer had to produce 1500 tools per day for each of the last 4 days to meet the schedule

Meh. Obviously neither of the statements is sufficient on its own. I guess they want you to think that the combination is sufficient (600+ 4*1500 = 6600, so N=7). The problem is that the statements are phrased as "the first 5 days" and "the last 4 days" - not "the first 5 days" and the "NEXT four days". Between the first 5 and the last 4, you can sneak in a whole YEAR of working at exactly 1000 tools per day - there's no requirement that the last 4 come immediately after the first 5. Answer should be E.

EDIT: 600 for the first 5 days altogether, not 600 per day. Doesn't matter.

Geva
Senior Instructor
Master GMAT
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https://www.mastergmat.com

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worldpeace93: Junior | Next Rank: 30 Posts; Posts: 21; Joined: Sun Jun 05, 2011 10:39 pmFollowed by: 1 member; Thanked: 2 times

by worldpeace93 » Mon Jun 20, 2011 10:34 pm

Answer should be E,as both statements combined or alone don't metion the total no of working days.

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bubbliiiiiiii: Legendary Member; Posts: 979; Joined: Tue Apr 14, 2009 1:38 amFollowed by: 12 members; Location: Hyderabad, India; Thanked: 49 times; GMAT Score:700

by bubbliiiiiiii » Tue Jun 21, 2011 12:28 am

Thanks Geva@MasterGMAT sir for your insights.

Even I picked C and then later understood why E and not C.

Regards,

Pranay

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ChrisK: Newbie | Next Rank: 10 Posts; Posts: 3; Joined: Fri Oct 22, 2010 2:08 am

by ChrisK » Tue Jun 21, 2011 2:53 am

Thanks guys, that was a critical oversight on my part.

Sorry Bens.

Chris

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Bens4vcobra: Senior | Next Rank: 100 Posts; Posts: 76; Joined: Thu Feb 19, 2009 12:10 pmFollowed by: 2 members; Thanked: 3 times

by Bens4vcobra » Tue Jun 21, 2011 6:29 am

ChrisK wrote:Thanks guys, that was a critical oversight on my part.

Sorry Bens.

Chris

No problem I did exactly what you did! I assumed the total days were 9 and that the order was filled on schedule. I fell for the trap.

Last edited by Bens4vcobra on Tue Jun 21, 2011 6:31 am, edited 1 time in total.

"It takes no ability to give effort. Toughness is not God-given; it's a choice. The discipline to execute is a habit." - Nick Saban

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Bens4vcobra: Senior | Next Rank: 100 Posts; Posts: 76; Joined: Thu Feb 19, 2009 12:10 pmFollowed by: 2 members; Thanked: 3 times

by Bens4vcobra » Tue Jun 21, 2011 6:30 am

Frankenstein wrote:
Bens4vcobra wrote: 1) Because of production problems, the manufacturer only produced 600 tools for the first 5 days
Hi,
Can you check statement(1) again. Is it 600tools per day for the first 5 days? Please check for errors while posting the question.

Pretty sure I typed the question correctly.

"It takes no ability to give effort. Toughness is not God-given; it's a choice. The discipline to execute is a habit." - Nick Saban

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Sanjay2706: Master | Next Rank: 500 Posts; Posts: 116; Joined: Tue May 31, 2011 7:52 pmFollowed by: 2 members; Location: Bangalore, India; Thanked: 2 times

by Sanjay2706 » Mon Jun 27, 2011 2:04 am

Answer is E, as it is not clear whether there were only 9 days.
The first 5 days and last 4 days does not mean that there were only 9 days.
Tricky one.

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