Algebra: Applied Problems

Expert replies

tvd04c: Newbie | Next Rank: 10 Posts; Posts: 3; Joined: Tue Mar 22, 2011 12:01 pm

by tvd04c » Fri Apr 01, 2011 6:11 pm

At a loading dock, each worker on the night crew loaded 3/4 as many boxes as each worker on the day crew. If the night crew has 4/5 as many workers as the day crew, what fraction of all the boxes loaded by the two crews did the day crew load?

a. 1/2
b. 2/5
c. 3/5
d. 4/5
e. 5/8

Answer: the workers on the night crew will load 3/4(4/5)=3/5 as many boxes as the day crew. Total loaded by both day and night crews is thus 1+3/5=8/5 of the day crew's work. Therefore 1/(8/5)=5/8 or E.

This is the answer given by the OG 11th edition. Can someone work this problem in a different way because I don't understand the explanation.

Like this post

Source: Beat The GMAT — Problem Solving | Fri Apr 01, 2011 6:11 pm

GMATGuruNY: GMAT Instructor; Posts: 15539; Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members; Location: New York, NY; Thanked: 13060 times; GMAT Score:790

by GMATGuruNY » Fri Apr 01, 2011 6:19 pm

tvd04c wrote:At a loading dock, each worker on the night crew loaded 3/4 as many boxes as each worker on the day crew. If the night crew has 4/5 as many workers as the day crew, what fraction of all the boxes loaded by the two crews did the day crew load?

a. 1/2
b. 2/5
c. 3/5
d. 4/5
e. 5/8

Answer: the workers on the night crew will load 3/4(4/5)=3/5 as many boxes as the day crew. Total loaded by both day and night crews is thus 1+3/5=8/5 of the day crew's work. Therefore 1/(8/5)=5/8 or E.

This is the answer given by the OG 11th edition. Can someone work this problem in a different way because I don't understand the explanation.

Let the number of day crew workers = 5.
Then the number of night crew workers = 4/5 * 5 = 4.

Let the number of boxes loaded by each day crew worker = 4.
Then the number of boxes loaded by each night crew worker = 3/4 * 4 = 3.

Total boxes loaded by the day crew = 5*4 = 20.
Total boxes loaded by the night crew = 4*3 = 12.
Day crew boxes/Total boxes = 20/(20+12) = 20/32 = 5/8.

The correct answer is E.

Last edited by GMATGuruNY on Sat Nov 12, 2011 12:18 pm, edited 1 time in total.

Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3

Like this post

manpsingh87: Master | Next Rank: 500 Posts; Posts: 436; Joined: Tue Feb 08, 2011 3:07 amFollowed by: 6 members; Thanked: 72 times

by manpsingh87 » Sat Apr 02, 2011 12:02 am

tvd04c wrote:At a loading dock, each worker on the night crew loaded 3/4 as many boxes as each worker on the day crew. If the night crew has 4/5 as many workers as the day crew, what fraction of all the boxes loaded by the two crews did the day crew load?

a. 1/2
b. 2/5
c. 3/5
d. 4/5
e. 5/8

Answer: the workers on the night crew will load 3/4(4/5)=3/5 as many boxes as the day crew. Total loaded by both day and night crews is thus 1+3/5=8/5 of the day crew's work. Therefore 1/(8/5)=5/8 or E.

This is the answer given by the OG 11th edition. Can someone work this problem in a different way because I don't understand the explanation.

let each worker of day crew loads x boxes, therefore each worker of the night crew loads (3/4)x boxes
let day crew has y workers, therefore night crew has (4/5)y workers,
total boxes loaded by the day crew=x*y;
total boxes loaded by the night crew=(3/4)x*(4/5)y=(3/5)xy;
total boxes loaded by all the crew=x*y+(3/5)x*y=(8/5)xy;
therefore the required fraction= xy/(8/5)xy=5/8 hence E

O Excellence... my search for you is on... you can be far.. but not beyond my reach!

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

563 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (563 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review