GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 16 Nov 2018, 22:50

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 November
PrevNext
SuMoTuWeThFrSa
28293031123
45678910
11121314151617
18192021222324
2526272829301
Open Detailed Calendar
• Free GMAT Strategy Webinar

November 17, 2018

November 17, 2018

07:00 AM PST

09:00 AM PST

Nov. 17, 7 AM PST. Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.
• GMATbuster's Weekly GMAT Quant Quiz # 9

November 17, 2018

November 17, 2018

09:00 AM PST

11:00 AM PST

Join the Quiz Saturday November 17th, 9 AM PST. The Quiz will last approximately 2 hours. Make sure you are on time or you will be at a disadvantage.

'Work' Word Problems Made Easy

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

Hide Tags

CEO
Joined: 20 Mar 2014
Posts: 2635
Concentration: Finance, Strategy
Schools: Kellogg '18 (M)
GMAT 1: 750 Q49 V44
GPA: 3.7
WE: Engineering (Aerospace and Defense)
Re: 'Work' Word Problems Made Easy  [#permalink]

Show Tags

30 Jul 2015, 08:38
1
JRAppz wrote:
Can someone help with this question?
If it takes 4 machines, working at the same constant rate, 2 hours to complete 2 jobs, how long will it take 3 machines, working at the same constant rate, to complete 3 jobs?"

The answer is 4 hours but I have no idea how to arrive at the answer, hopefully someone can help.

You can follow the method mentioned by Bunuel above .

The only thing you need to remember is that the work rate problems are similar to distance-speed-time wherein Distance is similar to job, speed is similar to rate and time is constant.

Thus, as distance = speed X time

Job or work = rate x time

Additionally, as with more machines, the total time required will reduce for the same amount of work, combined rates of 'n' machines will be n*rate of 1 machine.
CEO
Status: GMATINSIGHT Tutor
Joined: 08 Jul 2010
Posts: 2700
Location: India
GMAT: INSIGHT
WE: Education (Education)
Re: 'Work' Word Problems Made Easy  [#permalink]

Show Tags

30 Jul 2015, 09:27
JRAppz wrote:
Can someone help with this question?
If it takes 4 machines, working at the same constant rate, 2 hours to complete 2 jobs, how long will it take 3 machines, working at the same constant rate, to complete 3 jobs?"

The answer is 4 hours but I have no idea how to arrive at the answer, hopefully someone can help.

CONCEPT: $$\frac{(Machine_Power * Time)}{Work} = Constant$$

i.e. $$\frac{(M_1 * T_1)}{W_1} = \frac{(M_2 * T_2)}{W_2}$$

i.e. $$\frac{(4 * 2))}{2} = \frac{(3 * T_2)}{3}$$

i.e. $$T_2 = 4$$
_________________

Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

ACCESS FREE GMAT TESTS HERE:22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION

Current Student
Joined: 12 Aug 2015
Posts: 287
Concentration: General Management, Operations
GMAT 1: 640 Q40 V37
GMAT 2: 650 Q43 V36
GMAT 3: 600 Q47 V27
GPA: 3.3
WE: Management Consulting (Consulting)
Re: 'Work' Word Problems Made Easy  [#permalink]

Show Tags

02 Jan 2016, 06:03
hi can anyone help me with this concept please? i get confused why concept employed in Bunuel's example contradicts with the example given in this thread?

m30-184568.html#p1618937
_________________

KUDO me plenty

Manager
Joined: 03 May 2014
Posts: 161
Location: India
WE: Sales (Mutual Funds and Brokerage)

Show Tags

20 Mar 2016, 00:13
rainbooow wrote:
sriharimurthy wrote:
‘Work’ Word Problems Made Easy

We are told that B produces 10% more sprockets per hour than A, thus $$\frac{660}{t+10}*1.1=\frac{660}{t}$$ --> $$t=100$$ --> the rate of A is $$\frac{660}{t+10}=6$$ sprockets per hour.

Can someone explain to me how to get t=100? from this equation?

Thank you!

660/(t+10)X1.1=660/t

Multiply 660 by 1.1 you get 726.
The equation becomes 726/(t+10)=660/t
Now cross multiply the equation 726t=660t+6600
726t-660t=66T.
so the equation takes the form 66t=6600 or t= 6600/66= 100
Intern
Joined: 05 May 2016
Posts: 6
Location: India
Re: 'Work' Word Problems Made Easy  [#permalink]

Show Tags

09 May 2016, 11:59
example 4 =Machine A and Machine B are used to manufacture 660 sprockets. It takes machine A ten hours longer to produce 660 sprockets than machine B. Machine B produces 10% more sprockets per hour than machine A. How many sprockets per hour does machine A produce?
in this question solution
We are told that B produces 10% more sprockets per hour than A, thus 660t+10∗1.1=660t660t+10∗1.1=660t --> t=100t=100 --> the rate of A is 660t+10=6660t+10=6 sprockets per hour.

how did 1.1 come ..plz help
Intern
Joined: 22 Jun 2016
Posts: 7
Re: 'Work' Word Problems Made Easy  [#permalink]

Show Tags

02 Oct 2016, 04:43
sondenso wrote:
JoyLibs wrote:
Can someone help me solve this DS problem on 'Work'

A group of 5 craftsmen, working together at the same rate, can finish a job in 3 hours. How long will it take a group of 4 apprentices working together to do the same job?

(1) Each apprentice works at 2/3 the rate of a craftsman.
(2) The 5 craftsmen and the 4 apprentices working together will take 45/23 hours to finish the job.

x= time 4 apprentices need to do a job and what is x?
1.
1/(3*5) = (2/3)* {1/(4*x)}-->x is specific. suff

2.

1/(3*5) + 1/(4*x) = 23/45 --->x is specific, suff

D

I am just wondering shoudn't the first statement be be (2/3)*1/(3*5)={1/(4*x)} ?
Manager
Joined: 13 Dec 2013
Posts: 158
Location: United States (NY)
Concentration: Nonprofit, International Business
GMAT 1: 710 Q46 V41
GMAT 2: 720 Q48 V40
GPA: 4
WE: Consulting (Consulting)
Re: 'Work' Word Problems Made Easy  [#permalink]

Show Tags

23 Mar 2017, 21:30
JoyLibs wrote:
Can someone help me solve this DS problem on 'Work'

A group of 5 craftsmen, working together at the same rate, can finish a job in 3 hours. How long will it take a group of 4 apprentices working together to do the same job?

(1) Each apprentice works at 2/3 the rate of a craftsman.
(2) The 5 craftsmen and the 4 apprentices working together will take 45/23 hours to finish the job.

From stem: 5(1/C)=1/3, where C is the number hours taken by one craftsman to complete the job. 1/C=1/15, so each craftsman takes 15h to complete the job.

1) (2/3)*(1/15)=2/45=rate of one apprentice
rate of 4 apprentices is therefore 8/45. The apprentices take 45/8 h. Suff.

2) 5(1/C) + 4(1/A) = 23/45
1/3 + 4/A = 23/45
4/A= 23/45 - 1/3 = 69/135 - 45/135 = 24/135 = 8/45 = 45/8 h Suff.
SVP
Joined: 12 Dec 2016
Posts: 1674
Location: United States
GMAT 1: 700 Q49 V33
GPA: 3.64
Re: 'Work' Word Problems Made Easy  [#permalink]

Show Tags

13 May 2017, 14:35
some quantitative questions asks to find the total least amount of time, can sb pls help me with this, thanks.
For example, if A starts every 30 min, and it takes 1h20 to finish ride A.
B starts every 45 min, and it takes 50 min to fnish ride B
.......
what is the least total amount of time?

How to solve this question in less than 2 min???
Intern
Joined: 04 Aug 2014
Posts: 3

Show Tags

09 Mar 2018, 00:26
rainbooow wrote:
sriharimurthy wrote:
‘Work’ Word Problems Made Easy

We are told that B produces 10% more sprockets per hour than A, thus $$\frac{660}{t+10}*1.1=\frac{660}{t}$$ --> $$t=100$$ --> the rate of A is $$\frac{660}{t+10}=6$$ sprockets per hour.

Can someone explain to me how to get t=100? from this equation?

Thank you!

Bumping this question up: How do we quickly solve 660/(t+10)*1.1=660/t --> t=100?

I understand we can multiply both sides by t(t+10) to get rid of the denominators, but solving this way involves some serious computations (which I would take me several minutes, I'm afraid...). Is there a faster way?
Intern
Joined: 03 Feb 2016
Posts: 13
Location: China
Re: 'Work' Word Problems Made Easy  [#permalink]

Show Tags

09 Sep 2018, 19:10
Ziggygee11 - I think the Answer to your question is 24.

This is how i solved it:

40/t+4 + 40/t = 50/6

Solving this you get t =8

So A' rate = 10/3

For 80 pages it will be 80*3/10 = 24
VP
Joined: 09 Mar 2016
Posts: 1076

Show Tags

29 Sep 2018, 06:09
sriharimurthy wrote:

Example 3.
Working together, printer A and printer B would finish a task in 24 minutes. Printer A alone would finish the task in 60 minutes. How many pages does the task contain if printer B prints 5 pages a minute more than printer A?

Solution:
This problem is interesting because it tests not only our knowledge of the concept of word problems, but also our ability to ‘translate English to Math’

‘Working together, printer A and printer B would finish a task in 24 minutes’ This tells us that A and B combined would work at the rate of $$\frac{1}{24}$$ per minute.

‘Printer A alone would finish the task in 60 minutes’ This tells us that A works at a rate of $$\frac{1}{60}$$ per minute.

At this point, it should strike you that with just this much information, it is possible to calculate the rate at which B works: Rate at which B works = $$\frac{1}{24}-\frac{1}{60}=\frac{1}{40}$$.

‘B prints 5 pages a minute more than printer A’ This means that the difference between the amount of work B and A complete in one minute corresponds to 5 pages. So, let us calculate that difference. It will be $$\frac{1}{40}-\frac{1}{60}=\frac{1}{120}$$

‘How many pages does the task contain?’ If $$\frac{1}{120}$$ of the job consists of 5 pages, then the 1 job will consist of $$\frac{(5*1)}{\frac{1}{120}} = 600$$ pages.

if in denominator always is given time (unless is reversed ) $$\frac{1}{120}$$ then how can 120 be amount of work ? what does 5*1 mean ? and why are we dividing by 1/120 to get WORK DONE

as per FORMULA ---> WORK = RATE * TIME

pls explain
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 8540
Location: Pune, India
Re: 'Work' Word Problems Made Easy  [#permalink]

Show Tags

01 Oct 2018, 02:41
1
1
dave13 wrote:
sriharimurthy wrote:

Example 3.
Working together, printer A and printer B would finish a task in 24 minutes. Printer A alone would finish the task in 60 minutes. How many pages does the task contain if printer B prints 5 pages a minute more than printer A?

Solution:
This problem is interesting because it tests not only our knowledge of the concept of word problems, but also our ability to ‘translate English to Math’

‘Working together, printer A and printer B would finish a task in 24 minutes’ This tells us that A and B combined would work at the rate of $$\frac{1}{24}$$ per minute.

‘Printer A alone would finish the task in 60 minutes’ This tells us that A works at a rate of $$\frac{1}{60}$$ per minute.

At this point, it should strike you that with just this much information, it is possible to calculate the rate at which B works: Rate at which B works = $$\frac{1}{24}-\frac{1}{60}=\frac{1}{40}$$.

‘B prints 5 pages a minute more than printer A’ This means that the difference between the amount of work B and A complete in one minute corresponds to 5 pages. So, let us calculate that difference. It will be $$\frac{1}{40}-\frac{1}{60}=\frac{1}{120}$$

‘How many pages does the task contain?’ If $$\frac{1}{120}$$ of the job consists of 5 pages, then the 1 job will consist of $$\frac{(5*1)}{\frac{1}{120}} = 600$$ pages.

if in denominator always is given time (unless is reversed ) $$\frac{1}{120}$$ then how can 120 be amount of work ? what does 5*1 mean ? and why are we dividing by 1/120 to get WORK DONE

as per FORMULA ---> WORK = RATE * TIME

pls explain

Imp: Ensure that you always have your eye on the units. When you are flipping a quantity, know why.

A and B finish a task in 24 mins. If work done has to be 1 (complete work), their rate of work is (1/24)th of the work per min. (It is usually the case that we consider work to be 1 work)

Work = Rate*Time
1 work = Rate* 24 mins
Rate = (1/24)th of work per min

Similarly, A's rate of work = (1/60)th of work per min

Since rates are additive, we get that B's rate must be (1/40)th of work per min.

So B does (1/40)th of the work in a min while B does only (1/60)th of the work. We are given that this difference of (1/40)th work and (1/60)th work is 5 pages.
So 1 complete work is 600 pages.
Now the rate of work can be expressed in terms of pages/min too.
B prints (1/40)*600 = 15 pages/min
A prints (1/60)*600 = 10 pages/min
_________________

Karishma
Veritas Prep GMAT Instructor

Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >

GMAT self-study has never been more personalized or more fun. Try ORION Free!

Re: 'Work' Word Problems Made Easy &nbs [#permalink] 01 Oct 2018, 02:41

Go to page   Previous    1   2   3   [ 52 posts ]

Display posts from previous: Sort by

'Work' Word Problems Made Easy

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.