GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

It is currently 03 Jul 2020, 09:35

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

A new copy machine can run off 1,500 workbooks in 8 hours, while it ta

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

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 64938
A new copy machine can run off 1,500 workbooks in 8 hours, while it ta  [#permalink]

Show Tags

New post 07 Aug 2019, 02:45
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

84% (01:59) correct 16% (02:58) wrong based on 49 sessions

HideShow timer Statistics

A new copy machine can run off 1,500 workbooks in 8 hours, while it takes on older copy machine 12 hours to do the same job. What is the total number of hours that it would take both copy machines working at the same time, but independently, to run off the 1,500 workbooks?

(A) 4.4
(B) 4.6
(C) 4.8
(D) 5
(E) 10

_________________
Director
Director
User avatar
D
Joined: 16 Jan 2019
Posts: 649
Location: India
Concentration: General Management
WE: Sales (Other)
Re: A new copy machine can run off 1,500 workbooks in 8 hours, while it ta  [#permalink]

Show Tags

New post 07 Aug 2019, 03:01
1
Work rate of new copier \(= \frac{1500}{8} = \frac{375}{2}\)

Work rate of old copier \(= \frac{1500}{12} = \frac{250}{2}\)

Combined work rate \(= \frac{375}{2}+\frac{250}{2}=\frac{625}{2}\)

So we have

\(\frac{625}{2}*hours=1500\)

Hours\(=\frac{1500*2}{625}=4.8\)

Answer is (C)

Posted from my mobile device
Manager
Manager
avatar
G
Joined: 03 Apr 2015
Posts: 247
GMAT 1: 650 Q49 V31
GPA: 3.59
Reviews Badge
Re: A new copy machine can run off 1,500 workbooks in 8 hours, while it ta  [#permalink]

Show Tags

New post 07 Aug 2019, 03:16
as all the work done by both machines and the combined rate work is same treat 1500 copies as 1 work

so new m/C 1 work in 8 hrs
so in 1 hr -------------1/8 work

similarly for old M/C
1hr----------------1/12 work

net work by both m/c in 1 hr = 1/8+1/12= 20/96

so time taken will be 96/20 hrs to complete one work therefore 1500 copies
=4.8 hrs
C
VP
VP
User avatar
D
Joined: 31 Oct 2013
Posts: 1491
Concentration: Accounting, Finance
GPA: 3.68
WE: Analyst (Accounting)
Re: A new copy machine can run off 1,500 workbooks in 8 hours, while it ta  [#permalink]

Show Tags

New post 07 Aug 2019, 03:17
Bunuel wrote:
A new copy machine can run off 1,500 workbooks in 8 hours, while it takes on older copy machine 12 hours to do the same job. What is the total number of hours that it would take both copy machines working at the same time, but independently, to run off the 1,500 workbooks?

(A) 4.4
(B) 4.6
(C) 4.8
(D) 5
(E) 10



Time needed for both machine to produce 1500 units is given.

1/8 + 1/12

= 5/24

I hrs work done by both machine.

24/5 = 4.8.

Time needed to complete the entire work.

******* 1500 units must be considered as a single work. units are same for both machine. Therefore we don't need to do anything with units.

C is the correct answer.
Target Test Prep Representative
User avatar
V
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 11006
Location: United States (CA)
Re: A new copy machine can run off 1,500 workbooks in 8 hours, while it ta  [#permalink]

Show Tags

New post 12 Aug 2019, 10:53
Bunuel wrote:
A new copy machine can run off 1,500 workbooks in 8 hours, while it takes on older copy machine 12 hours to do the same job. What is the total number of hours that it would take both copy machines working at the same time, but independently, to run off the 1,500 workbooks?

(A) 4.4
(B) 4.6
(C) 4.8
(D) 5
(E) 10



Let T be the number of hours to complete the job when both machines are running. We can create the following equation:

1500/8 * T + 1500/12 * T = 1500

T/8 + T/12 = 1

Let’s multiply each side by 24:

3T + 2T = 24

5T = 24

T = 4.8 hours

Answer: C
_________________

Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
225 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

GMAT Club Bot
Re: A new copy machine can run off 1,500 workbooks in 8 hours, while it ta   [#permalink] 12 Aug 2019, 10:53

A new copy machine can run off 1,500 workbooks in 8 hours, while it ta

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





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne