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

 It is currently 13 Dec 2018, 07:55

Stanford Chat (Calls Started)  |  Wharton Chat  (Calls Expected Soon)  |  Fuqua Chat (Calls Expected Soon)

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 December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
• The winning strategy for 700+ on the GMAT

December 13, 2018

December 13, 2018

08:00 AM PST

09:00 AM PST

What people who reach the high 700's do differently? We're going to share insights, tips and strategies from data we collected on over 50,000 students who used examPAL.
• GMATbuster's Weekly GMAT Quant Quiz, Tomorrow, Saturday at 9 AM PST

December 14, 2018

December 14, 2018

09:00 AM PST

10:00 AM PST

10 Questions will be posted on the forum and we will post a reply in this Topic with a link to each question. There are prizes for the winners.

One machine, working at a constant rate, can fill a certain production

Author Message
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 51185
One machine, working at a constant rate, can fill a certain production  [#permalink]

Show Tags

04 Apr 2018, 22:52
00:00

Difficulty:

15% (low)

Question Stats:

93% (00:32) correct 7% (00:32) wrong based on 73 sessions

HideShow timer Statistics

One machine, working at a constant rate, can fill a certain production order in 8 hours. How long would it take four identical machines, working at the same constant rate, to fill the order?

A. 2 hours
B. 4 hours
C. 8 hours
D. 16 hours
E. 32 hours

_________________
Manager
Joined: 17 May 2016
Posts: 182
Location: India
GMAT 1: 710 Q48 V40
WE: Marketing (Education)
Re: One machine, working at a constant rate, can fill a certain production  [#permalink]

Show Tags

04 Apr 2018, 22:58
Bunuel wrote:
One machine, working at a constant rate, can fill a certain production order in 8 hours. How long would it take four identical machines, working at the same constant rate, to fill the order?

A. 2 hours
B. 4 hours
C. 8 hours
D. 16 hours
E. 32 hours
Work done in 8 hrs = 1
Work done in 1 hr = 1/8

Work done by 4 machines in 1 hr = 1/2
So full work will be done in 2 hrs.

Ans is option A

Sent from my A0001 using GMAT Club Forum mobile app
Manager
Joined: 17 Jan 2017
Posts: 61
Re: One machine, working at a constant rate, can fill a certain production  [#permalink]

Show Tags

05 Apr 2018, 00:55
R * T = W
1 machine 1/8
4 machines 4 * 1/8 = 1/2

Work(4 machines)=1/2*t=1
t=2

(A)
Senior PS Moderator
Joined: 26 Feb 2016
Posts: 3325
Location: India
GPA: 3.12
One machine, working at a constant rate, can fill a certain production  [#permalink]

Show Tags

05 Apr 2018, 07:21
Bunuel wrote:
One machine, working at a constant rate, can fill a certain production order in 8 hours. How long would it take four identical machines, working at the same constant rate, to fill the order?

A. 2 hours
B. 4 hours
C. 8 hours
D. 16 hours
E. 32 hours

If the total production order is 32 units,
one machine(time taken: 8 hours) will do the work at 4 units/hour.

4 such machines, working at the same constant rate, will do 16 units of work in an hour.

Therefore, the times taken by the four machines to fill the order is $$\frac{32}{16} = 2$$hours(Option A)
_________________

You've got what it takes, but it will take everything you've got

Manager
Joined: 03 Oct 2016
Posts: 127
One machine, working at a constant rate, can fill a certain production  [#permalink]

Show Tags

07 Apr 2018, 15:45
Bunuel wrote:
One machine, working at a constant rate, can fill a certain production order in 8 hours. How long would it take four identical machines, working at the same constant rate, to fill the order?

A. 2 hours
B. 4 hours
C. 8 hours
D. 16 hours
E. 32 hours

8 hrs for 1 unit of work(by single machine.)
1 hr for 1/8 unit of work(by single machine.)

1 machine 1/8 of work.
4 machines 4*(1/8) work=1/2 work. Hence, (A) it will take 2 hrs for 4 identical machines.
_________________

Non-Allergic To Kudos

Senior SC Moderator
Joined: 22 May 2016
Posts: 2204
One machine, working at a constant rate, can fill a certain production  [#permalink]

Show Tags

07 Apr 2018, 20:47
Bunuel wrote:
One machine, working at a constant rate, can fill a certain production order in 8 hours. How long would it take four identical machines, working at the same constant rate, to fill the order?

A. 2 hours
B. 4 hours
C. 8 hours
D. 16 hours
E. 32 hours

Modify $$RT = W$$. Add one variable to LHS.
Manipulate it the same way.

Let $$N$$ = Number of machines or workers
Modified formula: $$N*R*T = W$$
(N*R*T=W table makes this way easy to see)

Scenario 1:
One machine can finish the work in 8 hours
$$W = 1$$ job
$$T = 8$$ hours

Standard formula to find individual rate:$$RT=W$$
Rate of one machine, $$R=\frac{W}{T}$$
$$R = \frac{1}{8}$$

Scenario 2:
At that rate, how long will it take 4 machines to finish W?
$$N = 4, R = \frac{1}{8}, W = 1$$
$$N*R*T=W$$. So

$$T = \frac{W}{(N*R)}$$

$$T =\frac{1}{(4*\frac{1}{8})}$$

$$T=\frac{1}{(\frac{4}{8})}=\frac{1}{(\frac{1}{2})}=1*\frac{2}{1}=2$$ hours

BSchool Forum Moderator
Joined: 28 Mar 2017
Posts: 1223
Location: India
GMAT 1: 730 Q49 V41
GPA: 4
Re: One machine, working at a constant rate, can fill a certain production  [#permalink]

Show Tags

08 Apr 2018, 00:25
Bunuel wrote:
One machine, working at a constant rate, can fill a certain production order in 8 hours. How long would it take four identical machines, working at the same constant rate, to fill the order?

A. 2 hours
B. 4 hours
C. 8 hours
D. 16 hours
E. 32 hours

Straight 2 .....

Use unitary method to solve such questions:

1 machine ----------- 8 hours
4 machines ------------ 8/4 = 2 hours !

Ans = A
_________________
Target Test Prep Representative
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2830
Re: One machine, working at a constant rate, can fill a certain production  [#permalink]

Show Tags

10 Apr 2018, 10:05
Bunuel wrote:
One machine, working at a constant rate, can fill a certain production order in 8 hours. How long would it take four identical machines, working at the same constant rate, to fill the order?

A. 2 hours
B. 4 hours
C. 8 hours
D. 16 hours
E. 32 hours

Since the rate of one machine is 1/8, the rate of four machines is 4 x 1/8 = 1/2.

So it would take four machines 1/(1/2) = 2 hours to complete the order.

_________________

Jeffery Miller

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Re: One machine, working at a constant rate, can fill a certain production &nbs [#permalink] 10 Apr 2018, 10:05
Display posts from previous: Sort by