Last visit was: 24 Jul 2024, 15:26 It is currently 24 Jul 2024, 15:26
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
SORT BY:
Date
Tags:
Show Tags
Hide Tags
User avatar
Intern
Intern
Joined: 08 Oct 2009
Posts: 9
Own Kudos [?]: 64 [7]
Given Kudos: 1
Send PM
Most Helpful Reply
User avatar
Manager
Manager
Joined: 18 Aug 2009
Posts: 220
Own Kudos [?]: 345 [9]
Given Kudos: 16
Concentration: Accounting
Schools:UT at Austin, Indiana State University, UC at Berkeley
 Q47  V34 GMAT 2: 660  Q46  V35 GMAT 3: 700  Q49  V36
GPA: 3.8
WE 1: 5.5
WE 2: 5.5
WE 3: 6.0
Send PM
General Discussion
Math Expert
Joined: 02 Sep 2009
Posts: 94609
Own Kudos [?]: 643639 [2]
Given Kudos: 86737
Send PM
User avatar
Manager
Manager
Joined: 12 Oct 2009
Posts: 64
Own Kudos [?]: 147 [0]
Given Kudos: 3
Send PM
Re: Working together question [#permalink]
Bunuel wrote:
timmaxwell8 wrote:
30. Jonathan can type a 20 page document in 40 minutes, Susan can type it in 30 minutes, and Jack can type it in 24 minutes. Working together, how much time will it take them to type the same document?

A. 5 minutes
B. 10 minutes
C. 15 minutes
D. 18 minutes
E. 20 minutes


J=20/40=1/2per min
S=20/30=2/3per min
JK=20/24=5/6per min

In one min together 1/2+2/3+5/6=12/6=2 pages.

For 20 pages=20/2=10

B.



If the work involved here is to type the 20page document we can even avoid calculating time taken per page.
will this apporach backfire?

Regards
Asterix
"Time is of gr8 essence"
User avatar
Manager
Manager
Joined: 18 Jul 2009
Posts: 71
Own Kudos [?]: 254 [0]
Given Kudos: 37
Location: India
Concentration: Marketing
Schools:South Asian B-schools
 Q48  V18
Send PM
Re: Working together question [#permalink]
1/40+1/30+1/24 = 24/240 = 1/10 work per min = 10 min to complete work :wink:
User avatar
Senior Manager
Senior Manager
Joined: 01 Apr 2008
Posts: 389
Own Kudos [?]: 4144 [0]
Given Kudos: 18
Name: Ronak Amin
Schools: IIM Lucknow (IPMX) - Class of 2014
Send PM
Re: Working together question [#permalink]
Formula for time taken by 3 guys is:

t1*t2*t3 / ( t1*t2 + t2*t3 + t3*t1 ) , this might be lead to a faster calculation :)
Intern
Intern
Joined: 30 Sep 2017
Posts: 14
Own Kudos [?]: 10 [0]
Given Kudos: 0
Send PM
Re: Jonathan can type a 20 page document in 40 minutes, Susan [#permalink]
Apply W=R*T formula

r(Johnathan)=1/2
r(Susan)=2/3
r(Jack)=5/6

1/2+2/3+5/6
r(total)=2 pages/minute

Therefore , applying this back to rate work formula, we get

20=2*T
T=10 minutes

Sent from my ONEPLUS A3003 using GMAT Club Forum mobile app
Target Test Prep Representative
Joined: 14 Oct 2015
Status:Founder & CEO
Affiliations: Target Test Prep
Posts: 19191
Own Kudos [?]: 22718 [0]
Given Kudos: 286
Location: United States (CA)
Send PM
Re: Jonathan can type a 20 page document in 40 minutes, Susan [#permalink]
Expert Reply
timmaxwell8 wrote:
Jonathan can type a 20 page document in 40 minutes, Susan can type it in 30 minutes, and Jack can type it in 24 minutes. Working together, how much time will it take them to type the same document?

A. 5 minutes
B. 10 minutes
C. 15 minutes
D. 18 minutes
E. 20 minutes


Jonathan has a rate of 20/40 = 1/2 page per minute, Susan has a rate of 20/30 = 2/3, and Jack has a rate of 20/24 = 5/6.

The combined rate of all 3 is:

1/2 + 2/3 + 5/6 = 3/6 + 4/6 + 5/6 = 12/6 = 2. Thus, if we let t = the time it takes them to work together:

2t = 20

t = 10

Answer: B
Intern
Intern
Joined: 12 Oct 2017
Posts: 27
Own Kudos [?]: 9 [0]
Given Kudos: 16
Send PM
Jonathan can type a 20 page document in 40 minutes, Susan [#permalink]
In 1 minute:
- Jonathan can type: 20/40 = 1/2 page
- Susan can type: 20/30 = 2/3 page
- Jack can type: 20/24 = 5/6 page
=> if they work together, in 1 minute they can type: 1/2 + 2/3 + 5/6 = 2 pages
=> It takes 20/2 = 10 minutes to type a 20 page document.
----
 
User avatar
Non-Human User
Joined: 09 Sep 2013
Posts: 34080
Own Kudos [?]: 853 [0]
Given Kudos: 0
Send PM
Re: Jonathan can type a 20 page document in 40 minutes, Susan [#permalink]
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
GMAT Club Bot
Re: Jonathan can type a 20 page document in 40 minutes, Susan [#permalink]
Moderator:
Math Expert
94609 posts