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

It is currently 21 Sep 2018, 11:03

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

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

Math Revolution GMAT Instructor
User avatar
V
Joined: 16 Aug 2015
Posts: 6227
GMAT 1: 760 Q51 V42
GPA: 3.82
Premium Member
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
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

79% (01:18) correct 21% (01:13) wrong based on 100 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 t?

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

_________________

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.
"Only $99 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"

Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 6797
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
4
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
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


GMAT online Tutor

Ask GMAT Experts Forum Moderator
User avatar
V
Status: Preparing for GMAT
Joined: 25 Nov 2015
Posts: 927
Location: India
GPA: 3.64
GMAT ToolKit User Premium Member Reviews Badge CAT Tests
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...

VP
VP
avatar
P
Joined: 07 Dec 2014
Posts: 1087
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, 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
Math Revolution GMAT Instructor
User avatar
V
Joined: 16 Aug 2015
Posts: 6227
GMAT 1: 760 Q51 V42
GPA: 3.82
Premium Member
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.
"Only $99 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"

Director
Director
User avatar
P
Joined: 27 May 2012
Posts: 575
Premium Member
Re: There are 3 machines with the same work rate. If it took t hours for 3  [#permalink]

Show Tags

New post 15 Sep 2018, 04:07
1
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



Dear Moderator,
There seems to be a small typo here. Variable K has been mistakenly written instead of variable t. Hope you will look into this. Thank you.
_________________

- Stne

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 49300
Re: There are 3 machines with the same work rate. If it took t hours for 3  [#permalink]

Show Tags

New post 15 Sep 2018, 04:12
stne wrote:
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



Dear Moderator,
There seems to be a small typo here. Variable K has been mistakenly written instead of variable t. Hope you will look into this. Thank you.


_______________
Edited. Thank you.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Board of Directors
User avatar
P
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4031
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)
GMAT ToolKit User Premium Member
Re: There are 3 machines with the same work rate. If it took t hours for 3  [#permalink]

Show Tags

New post 15 Sep 2018, 08:05
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 t?

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

Let efficiency of each machine be "e"

So, \(3*e*t = 2*e*(t+2)\)

Or, \(3t = 2t + 4\)

Or, \(t = 4\), Answer must be (A) 4
_________________

Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )

Re: There are 3 machines with the same work rate. If it took t hours for 3 &nbs [#permalink] 15 Sep 2018, 08:05
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  

Events & Promotions

PREV
NEXT


GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| 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®.