Page 1 of 1 [ 5 posts ]
 Print view Previous topic | Next topic
Author Message
 Post subject: GMAT Prep(TM)Posted: Tue Aug 09, 2011 10:12 pm

Joined: Fri Jun 03, 2011 10:28 pm
Posts: 2
1) 7.51 8.22 7.86 8.36 8.09 7.83 8.30 8.01 7.73 8.25 7.96 8.53
A vending machine is designed to dispense 8 ounces of coffee into a cup. After a test that recorded the number of coffee in each of 1000 cups dispensed by the vending machine, the 12 listed amounts, in ounces, were selected from the data. If the 1000 recorded amounts have a mean of 8.1 ounces and a standard deviation of 0.3 ounce, how many of the 12 amounts are within 15 standard deviations of the mean?

WHY?

2) Three grades of milk are 1%, 2%, 3% fat by volume. If x gallons of 1% grade, y gallons of 2% grade, z gallons of 3 % grade are mixed to give x+y+z gallons of a 1.5% grade, what is x in terms of y and z?

WHY?

Top

 Post subject: Re: GMAT Prep(TM)Posted: Tue Aug 16, 2011 5:29 pm

Joined: Thu Feb 12, 2009 6:32 pm
Posts: 497
Please provide the Veritas text, page, and problem number. Or if the problems are from exams provided by Veritas, please provide (or email to help@veritasprep.com) screen copies.

Thanks.

- Veritas Help

Top

 Post subject: Re: GMAT Prep(TM)Posted: Sun Oct 09, 2011 3:32 pm

Joined: Mon Jul 11, 2011 10:56 pm
Posts: 2
diyora wrote:
1) 7.51 8.22 7.86 8.36 8.09 7.83 8.30 8.01 7.73 8.25 7.96 8.53
A vending machine is designed to dispense 8 ounces of coffee into a cup. After a test that recorded the number of coffee in each of 1000 cups dispensed by the vending machine, the 12 listed amounts, in ounces, were selected from the data. If the 1000 recorded amounts have a mean of 8.1 ounces and a standard deviation of 0.3 ounce, how many of the 12 amounts are within 15 standard deviations of the mean?

WHY?

2) Three grades of milk are 1%, 2%, 3% fat by volume. If x gallons of 1% grade, y gallons of 2% grade, z gallons of 3 % grade are mixed to give x+y+z gallons of a 1.5% grade, what is x in terms of y and z?

WHY?

Hi, hmmm this is a tricky problem! Not sure why the answer is either...because after apply 15 of the standard deviations, it yields a range of 3.60 - 12.60, which all of the 12 samples seem to fall under...

@VeritasHelp: Any insight into this?

As for the "grades of milk problem", here's how I went about it:

First translate the prompt into algebra:
x(0.01) * Y(0.02) * Z(0.03) = (x+y+z)(0.015)
Then distribute the (0.015) on the right-hand side:
x(0.01) * Y(0.02) * Z(0.03) = x(0.015) + y(0.015) + z(0.015)
Then just combine like terms and isolate the x on one side, this will eventually yield the answer equation of:
x = y + 3z

Top

 Post subject: Re: GMAT Prep(TM)Posted: Mon Oct 10, 2011 5:41 pm

Joined: Thu Jul 03, 2008 2:13 pm
Posts: 117
Hey Derek,

Good question - and you're right as the problem is written. But as the original question is written, it's 1.5 standard deviations (and not 15...I don't think many statistical sample sets go to 15 standard deviations!), so that's why the range is from 0.45 on either side of the mean, and only 11 of the 12 values fit.

Top

 Post subject: Re: GMAT Prep(TM)Posted: Mon Oct 10, 2011 7:55 pm

Joined: Mon Jul 11, 2011 10:56 pm
Posts: 2
VP_Brian wrote:
Hey Derek,

Good question - and you're right as the problem is written. But as the original question is written, it's 1.5 standard deviations (and not 15...I don't think many statistical sample sets go to 15 standard deviations!), so that's why the range is from 0.45 on either side of the mean, and only 11 of the 12 values fit.

Great! Phew! Thought I was missing something KEY there. Thanks Brian!

Top

 Display posts from previous: All posts1 day7 days2 weeks1 month3 months6 months1 year Sort by AuthorPost timeSubject AscendingDescending
 Page 1 of 1 [ 5 posts ]

 All times are UTC - 8 hours [ DST ]

#### Who is online

Users browsing this forum: No registered users and 1 guest

 You cannot post new topics in this forumYou cannot reply to topics in this forumYou cannot edit your posts in this forumYou cannot delete your posts in this forumYou cannot post attachments in this forum

 Search for: