It is currently 20 Nov 2017, 23:49

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

There are 3 machines with the same work rate. If it took t hours for 3

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

Hide Tags

Expert Post
Math Revolution GMAT Instructor
User avatar
P
Joined: 16 Aug 2015
Posts: 4330

Kudos [?]: 3044 [0], given: 0

GPA: 3.82
Premium Member CAT Tests
There are 3 machines with the same work rate. If it took t hours for 3 [#permalink]

Show Tags

New post 24 Oct 2017, 07:54
Expert's post
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

75% (01:32) correct 25% (00:58) wrong based on 65 sessions

HideShow timer Statistics

[GMAT math practice question]

There are 3 machines with the same work rate. If it took t hours for 3 machines to work and took t+2 hours for 2 machines when working together, what is the value of k?

A. 4
B. 5
C. 6
D. 7
E. 9
[Reveal] Spoiler: OA

_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
Find a 10% off coupon code for GMAT Club members.
“Receive 5 Math Questions & Solutions Daily”
Unlimited Access to over 120 free video lessons - try it yourself
See our Youtube demo

Kudos [?]: 3044 [0], given: 0

Expert Post
1 KUDOS received
Math Expert
User avatar
P
Joined: 02 Aug 2009
Posts: 5214

Kudos [?]: 5860 [1], given: 117

Re: There are 3 machines with the same work rate. If it took t hours for 3 [#permalink]

Show Tags

New post 24 Oct 2017, 08:08
1
This post received
KUDOS
Expert's post
MathRevolution wrote:
[GMAT math practice question]

There are 3 machines with the same work rate. If it took t hours for 3 machines to work and took t+2 hours for 2 machines when working together, what is the value of k?

A. 4
B. 5
C. 6
D. 7
E. 9


I am sure Q is asking value of t and k is a typo error..

speed si the same..
if 3 do it in t hours, ONE will do it in 3*t..
if 2 do it in t+2 hours, ONE will do it in 2*(t+2)=2t+4..

But the speed is SAME, so 3t=2t+4....t=4
A
_________________

Absolute modulus :http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html

Kudos [?]: 5860 [1], given: 117

Senior Manager
Senior Manager
User avatar
G
Status: Preparing for GMAT
Joined: 25 Nov 2015
Posts: 333

Kudos [?]: 109 [0], given: 323

Location: India
GPA: 3.64
GMAT ToolKit User Premium Member Reviews Badge
Re: There are 3 machines with the same work rate. If it took t hours for 3 [#permalink]

Show Tags

New post 24 Oct 2017, 08:38
The rate of work of each machine is the same.
Work done by 3 machines in 1 hr = \(\frac{1}{t}\)
Work done by 1 machine in 1 hr = \(\frac{1}{{3t}}\)
Work done by 2 machines in 1 hr = \(\frac{2}{{3t}}\) = \(\frac{1}{{t+2}}\)
\(\frac{2}{{3t}}\)=\(\frac{1}{{t+2}}\)
2t+4=3t
t=4

Answer A

Please give kudos, if u liked my post!
_________________

Please give kudos, if you like my post

When the going gets tough, the tough gets going...

Kudos [?]: 109 [0], given: 323

Director
Director
avatar
G
Joined: 07 Dec 2014
Posts: 837

Kudos [?]: 267 [0], given: 15

There are 3 machines with the same work rate. If it took t hours for 3 [#permalink]

Show Tags

New post 24 Oct 2017, 13:31
There are 3 machines with the same work rate. If it took t hours for 3 machines to work and took t+2 hours for 2 machines when working together, what is the value of k?

A. 4
B. 5
C. 6
D. 7
E. 9

2/3 rate➡3/2 time
3/2*t=t+2
t=4 hours
A

Kudos [?]: 267 [0], given: 15

Expert Post
Math Revolution GMAT Instructor
User avatar
P
Joined: 16 Aug 2015
Posts: 4330

Kudos [?]: 3044 [0], given: 0

GPA: 3.82
Premium Member CAT Tests
Re: There are 3 machines with the same work rate. If it took t hours for 3 [#permalink]

Show Tags

New post 26 Oct 2017, 00:46
=>

Assume X is the time one machine takes to work.

1/T=3/X and 1/T+2=2/X

X = 3T and X = 2(T+2).
We have 3T = 2T + 4 or T = 4.

Thus, the answer is A.

Answer: A
_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
Find a 10% off coupon code for GMAT Club members.
“Receive 5 Math Questions & Solutions Daily”
Unlimited Access to over 120 free video lessons - try it yourself
See our Youtube demo

Kudos [?]: 3044 [0], given: 0

Re: There are 3 machines with the same work rate. If it took t hours for 3   [#permalink] 26 Oct 2017, 00:46
Display posts from previous: Sort by

There are 3 machines with the same work rate. If it took t hours for 3

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


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

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®.