Author 
Message 
TAGS:

Hide Tags

Manager
Joined: 24 May 2010
Posts: 83

Lindsay can paint 1/x of a certain room in one hour [#permalink]
Show Tags
08 Aug 2010, 13:46
2
This post received KUDOS
22
This post was BOOKMARKED
Question Stats:
79% (02:28) correct
21% (01:50) wrong based on 828 sessions
HideShow timer Statistics
Lindsay can paint 1/x of a certain room in one hour. If Lindsay and Joseph, working together at their respective rates, can paint the room in one hour, what fraction of the room can Joseph paint in 20 minutes? A. 1/3x B. x/(x3) C. (x1)/3x D. x/(x1) E. (x1)/x
Official Answer and Stats are available only to registered users. Register/ Login.
Last edited by Bunuel on 31 Aug 2013, 05:35, edited 3 times in total.
Added the OA.



Senior Manager
Status: Time to step up the tempo
Joined: 24 Jun 2010
Posts: 408
Location: Milky way
Schools: ISB, Tepper  CMU, Chicago Booth, LSB

Re: Wrk Problem [#permalink]
Show Tags
08 Aug 2010, 21:14
1
This post received KUDOS
Answer is C  \((x1/3x)\) Given details: Rate at which L work 1/x Rate at which L&J work  x Rate at which J alone works  \((x1/x)\) Rate at which J alone works in 20 min.  \((x1/x) * (20/60) => (x1/x)*(1/3)\) On a side note, maybe this post needs to be moved to the Problem solving section.
_________________
Support GMAT Club by putting a GMAT Club badge on your blog



Math Expert
Joined: 02 Sep 2009
Posts: 39755

Re: Wrk Problem [#permalink]
Show Tags
09 Aug 2010, 03:12
14
This post received KUDOS
Expert's post
9
This post was BOOKMARKED



Manager
Joined: 09 Jan 2010
Posts: 125

Re: Wrk Problem [#permalink]
Show Tags
09 Aug 2010, 09:54
bunuel u always hit the nail to the point.......very easy explanation....thanks



Manager
Status: livin on a prayer!!
Joined: 12 May 2011
Posts: 121
Location: Australia

Re: Wrk Problem [#permalink]
Show Tags
28 Oct 2011, 16:31
Just wondering, if the job took say, 2.5 hours to complete, how would the answer change? I understand your working though Bunuel, it's very clear.
_________________
Aim for the sky! (800 in this case) If you like my post, please give me Kudos



Intern
Joined: 02 May 2013
Posts: 4

Re: Wrk Problem [#permalink]
Show Tags
02 May 2013, 12:00
Mindreko wrote: Just wondering,
if the job took say, 2.5 hours to complete, how would the answer change?
I understand your working though Bunuel, it's very clear. If the job takes Joseph and Lindsay 2.5 hours together to complete. and Lindsay take as regular 1/x hours to complete. Then the rate at which Jospeh works would be = 1/2.5  1/x = (x  2.5) / (2.5x) Hence, in 20 minutes 2.5 hours = 150 mins, so in 20 mins he would complete : 2 / 15 * (x  2.5 ) / (2.5 x )



Intern
Joined: 08 Nov 2012
Posts: 22

Re: Lindsay can paint 1/x of a certain room in one hour [#permalink]
Show Tags
08 May 2013, 17:17
if you use a smart number 2 for x, then A would be correct. I got this problem wrong two times so far in my studies and make the same mistake. Can someone explain why they would not think to use the number 2 as a smart number going into this problem?



MBA Section Director
Status: Back to work...
Affiliations: GMAT Club
Joined: 22 Feb 2012
Posts: 4404
Location: India
City: Pune
GPA: 3.4
WE: Business Development (Manufacturing)

Re: Lindsay can paint 1/x of a certain room in one hour [#permalink]
Show Tags
08 May 2013, 21:51
Richard0715 wrote: if you use a smart number 2 for x, then A would be correct. I got this problem wrong two times so far in my studies and make the same mistake. Can someone explain why they would not think to use the number 2 as a smart number going into this problem? Have you checked Option C using x=2 ? \(\frac{(x1)}{3x}\) > \(\frac{(21)}{3X2}\) > \(\frac{1}{6}\) > Same as Option A
_________________
Every Wednesday: Meet MBA Experts in Chat Room and Ask Your MostPressing MBA Admission Questions to them in a Live Chat.
Must Read Forum Topics Before You Kick Off Your MBA Application
New GMAT Club Decision Tracker  Real Time Decision Updates



Intern
Joined: 06 May 2013
Posts: 24

Lindsay can paint 1/x of a certain room in one hour. If Lind [#permalink]
Show Tags
04 Aug 2013, 09:07
Lindsay can paint 1/x of a certain room in one hour. If Lindsay and Joseph, working together at their respective rates, can paint the room in one hour, what fraction of the room can Joseph paint in 20 minutes? A)1/3x B)x/(x3) C)(x – 1)/3x D)x/(x1) E)(x – 1)/x I used substitution of values for the variable x, when x=2 i get an answer and when x=3 i get another answer! Please highlight my mistake.



Intern
Joined: 07 May 2011
Posts: 48
Location: United States
Concentration: Finance, Accounting
GPA: 3.94
WE: Accounting (Mutual Funds and Brokerage)

Re: A question in VICs [#permalink]
Show Tags
04 Aug 2013, 11:21
pjagadish27 wrote: Lindsay can paint 1/x of a certain room in one hour. If Lindsay and Joseph, working together at their respective rates, can paint the room in one hour, what fraction of the room can Joseph paint in 20 minutes? A)1/3x B)x/(x3) C)(x – 1)/3x D)x/(x1) E)(x – 1)/x I used substitution of values for the variable x, when x=2 i get an answer and when x=3 i get another answer! Please highlight my mistake. Wrong forum, but here we go: Let x=2: Lindsay paints 1/2 room in 1 hour. You can use the RTD formula. R*1=1/2, then R=1/2. Let Joseph's rate = 1/y, they say that combined they can paint the room in 1 hour, so: (1/2+1/y)*1=1, solve for y. Y is = to 1/6. 1/6 become your target value. Insert 2 in each answer choices, you will see that it only works for C. I think you made a mistake as you were not sure what was your actual target value.



Intern
Joined: 06 May 2013
Posts: 24

Re: A question in VICs [#permalink]
Show Tags
04 Aug 2013, 23:23
Hi jinkev,
When x=2 is put in option A, ans =1/(3*2)=1/6. Also when x=2 in option C, ans=(21)/(3*2)=1/6. So how should i proceed now. Should I try with some other value for x?



MBA Section Director
Status: Back to work...
Affiliations: GMAT Club
Joined: 22 Feb 2012
Posts: 4404
Location: India
City: Pune
GPA: 3.4
WE: Business Development (Manufacturing)

Re: A question in VICs [#permalink]
Show Tags
05 Aug 2013, 01:29
3
This post received KUDOS
Expert's post
1
This post was BOOKMARKED
Well, I am not a fond of trying values or of backsolving methods. So I will present different method to solve this one  Percent Method. First some theory.When we say a person can finish the given task in X hours, we can also say that he can finish \(\frac{100}{X}%\) task in one hour (Whole task always equals to 100%) When we say another person can finish the same task in Y hours, we can also say that he can finish \(\frac{100}{Y}%\) task in one hour. Finally we can say that they can finish \((\frac{100}{X} + \frac{100}{Y})%\) task in one hour. We will try this method in a simple question Q : A can finish certain work in 10 days. B can finish the same work in 20 days. In how many days can they finish the work working together? A can finish certain work in 10 days > He can complete 10% of the work in a day B can finish the same work in 20 days. > He can complete 5% of the work in a day Working together they can complete (10+5)% work in a day. Now that we know Total work always equals 100% and that they are finishing 15% work in a day working together, So we can say that they can complete the total work in \(\frac{100}{15}\) (i.e. 6.66) days. Back to your question..........Lindsay can paint \(\frac{1}{X}\) of a certain room in one hour. > This simply states that Lindsay can paint the room in X hours > Lindsay can paint \((\frac{100}{X})%\) of the room in one hour Lindsay and Joseph, working together at their respective rates, can paint the room in one hour > Working together they can paint the 100% of the room in one hour Equation is ( Rate of Lindsay of one hour + Joseph Rate of of one hour) = Rate of Lindsay+Joseph of one hour \(\frac{100}{X}\) + Joseph Rate of of one hour = 100 > Joseph's Rate of one hour = \(100  \frac{100}{X}\) > Joseph's Rate of one hour = \(\frac{100(X  1)}{X}\) > We can rephrase this as Joseph is completing \(\frac{(100(X1))}{X}%\) of 100% room in one hour > In Fraction He is completing \(\frac{(100(X1))}{100X}\) in one hour > \(\frac{(X1)}{X}\) what fraction of the room can Joseph paint in 20 minutes? > what fraction of the room can Joseph paint in \(\frac{1}{3}\) hour? > \(\frac{1}{3} \frac{(x1)}{x}\) > \(\frac{(x1)}{3x}\) Option CHope that Helps. PS : This question is already discussed here lindsaycanpaint1xofacertainroominonehour98789.html#p761312
_________________
Every Wednesday: Meet MBA Experts in Chat Room and Ask Your MostPressing MBA Admission Questions to them in a Live Chat.
Must Read Forum Topics Before You Kick Off Your MBA Application
New GMAT Club Decision Tracker  Real Time Decision Updates



Director
Joined: 14 Dec 2012
Posts: 832
Location: India
Concentration: General Management, Operations
GPA: 3.6

Re: A question in VICs [#permalink]
Show Tags
05 Aug 2013, 01:50
2
This post received KUDOS
1
This post was BOOKMARKED
pjagadish27 wrote: Lindsay can paint 1/x of a certain room in one hour. If Lindsay and Joseph, working together at their respective rates, can paint the room in one hour, what fraction of the room can Joseph paint in 20 minutes? A)1/3x B)x/(x3) C)(x – 1)/3x D)x/(x1) E)(x – 1)/x I used substitution of values for the variable x, when x=2 i get an answer and when x=3 i get another answer! Please highlight my mistake. LINDSAY ==> 1/X of room in 1 hr LINDSAY + JOSEPH ==> FULL ROOM i.e 1 ROOM IN 1 HR JOSEPH 1 HR WORK + LINDSAY 1 HR WORK = FULL ROOM PAINTING = 1 JOSEPH 1 HR WORK + 1/X = 1 JOSEPH 1 HR WORK = 1 1/X = (X1)X THEREFORE JOSEPH WORK IN 20 MINUTES(1/3 OF HOUR) =\((1/3)*((X1)/X)\) = \((X1)/3X\) Hope this helps
_________________
When you want to succeed as bad as you want to breathe ...then you will be successfull....
GIVE VALUE TO OFFICIAL QUESTIONS...
GMAT RCs VOCABULARY LIST: http://gmatclub.com/forum/vocabularylistforgmatreadingcomprehension155228.html learn AWA writing techniques while watching video : http://www.gmatprepnow.com/module/gmatanalyticalwritingassessment : http://www.youtube.com/watch?v=APt9ITygGss



Intern
Joined: 17 May 2013
Posts: 49
GMAT Date: 10232013

Re: A question in VICs [#permalink]
Show Tags
05 Aug 2013, 18:12
Let Joseph rate of work in 1 hr be y Given : Lindsay rate of work in 1 hr as 1/x
Together,
1/x + y = 1
So Joseph rate of work would be
y = 1  1/x ==> x1/x
In 20 min(1/3 of an hour), it would be 1/3(x1/x) ==> x1/3x Option C



Senior Manager
Joined: 10 Jul 2013
Posts: 334

Re: Lindsay can paint 1/x of a certain room in one hour [#permalink]
Show Tags
12 Aug 2013, 15:24
Jinglander wrote: Lindsay can paint 1/x of a certain room in one hour. If Lindsay and Joseph, working together at their respective rates, can paint the room in one hour, what fraction of the room can Joseph paint in 20 minutes?
A. 1/3x B. x/(x3) C. (x1)/3x D. x/(x1) E. (x1)/x .................. 1/x + 1/j = 1/1 or, j = x/(x1) hours x/(x1) hours = 1 part or, 20/60 hours = (x1)/3x part
_________________
Asif vai.....



Manager
Joined: 07 May 2013
Posts: 109

Re: Lindsay can paint 1/x of a certain room in one hour [#permalink]
Show Tags
30 Aug 2013, 16:58
1/x th of work1 hr 1 full work? hr x hrs by L to complete full work
Now xy/x+y=1 we have to find y i.e., hrs taken by J to complete full work
divide numerator and denominator of L.H.S with y we get x divided by (x+y)*1/y=1 x=(x+y)*1/y x=x/y+1 x1=x/y x1/x=1/y reciprocal both sides x/x1=y
Now it takes x/x1 hrs to complete 1 full work by J then in 1/3 hrs i.e., 20 min ? work J completes
=1/3*1 whole divided by (x/x1) =1/3*(x1/x) =x1/3x



Intern
Joined: 10 Dec 2014
Posts: 1

Solving equation question Manhatten GMAT cat test [#permalink]
Show Tags
10 Dec 2014, 02:34
Hi all,
I have a problem to understand the explanation (in red) as given by the Manhatten GMAT test; question (Q) is as follows and explanation (E):
Q: Lindsay can paint 1/x of a certain room in one hour. If Lindsay and Joseph, working together at their respective rates, can paint the room in one hour, what fraction of the room can Joseph paint in 20 minutes?
E:
The work Lindsay does + the work Joseph does = the total work done. Let's say that the work Joseph does is 1/y.
Then we have this equation: 1/x + 1/y = 1
Solving for 1/y, we get 1/y = 1  1/x. The righthand side of the equation simplifies to the following expression:
x – 1/x
So, how to come from 1/y= 11/x to x1/x??
Hope to hear from you guys,
Kind regards,
Mathijs



SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1857
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)

Solving equation question Manhatten GMAT cat test [#permalink]
Show Tags
10 Dec 2014, 02:37
1
This post received KUDOS
Rate of Lindsay \(= \frac{1}{60x}\) Rate of Joseph \(= \frac{1}{60}  \frac{1}{60x} = \frac{x1}{60x}\) Work done by Joseph in 20 Minutes \(= \frac{x1}{60x} * 20 = \frac{x1}{3x}\)
_________________
Kindly press "+1 Kudos" to appreciate
Last edited by PareshGmat on 10 Dec 2014, 02:48, edited 1 time in total.



SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1857
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)

Re: Solving equation question Manhatten GMAT cat test [#permalink]
Show Tags
10 Dec 2014, 02:45
Mathijs wrote: Hi all,
I have a problem to understand the explanation (in red) as given by the Manhatten GMAT test; question (Q) is as follows and explanation (E):
Q: Lindsay can paint 1/x of a certain room in one hour. If Lindsay and Joseph, working together at their respective rates, can paint the room in one hour, what fraction of the room can Joseph paint in 20 minutes?
E:
The work Lindsay does + the work Joseph does = the total work done. Let's say that the work Joseph does is 1/y.
Then we have this equation: 1/x + 1/y = 1
Solving for 1/y, we get 1/y = 1  1/x. The righthand side of the equation simplifies to the following expression:
x – 1/x
So, how to come from 1/y= 11/x to x1/x??
Hope to hear from you guys,
Kind regards,
Mathijs This problem is posted complete at the link below: lindsaycanpaint1xofacertainroominonehour98789.htmlPlease refer
_________________
Kindly press "+1 Kudos" to appreciate



Math Expert
Joined: 02 Sep 2009
Posts: 39755

Re: Lindsay can paint 1/x of a certain room in one hour [#permalink]
Show Tags
10 Dec 2014, 04:06
Mathijs wrote: Hi all,
I have a problem to understand the explanation (in red) as given by the Manhatten GMAT test; question (Q) is as follows and explanation (E):
Q: Lindsay can paint 1/x of a certain room in one hour. If Lindsay and Joseph, working together at their respective rates, can paint the room in one hour, what fraction of the room can Joseph paint in 20 minutes?
E:
The work Lindsay does + the work Joseph does = the total work done. Let's say that the work Joseph does is 1/y.
Then we have this equation: 1/x + 1/y = 1
Solving for 1/y, we get 1/y = 1  1/x. The righthand side of the equation simplifies to the following expression:
x – 1/x
So, how to come from 1/y= 11/x to x1/x??
Hope to hear from you guys,
Kind regards,
Mathijs Merging topics. Please refer to the discussion above and ask if anything is still unclear. Similar question to practice: lindsaycanpaint1xofacertainroomin20minuteswhat156880.htmlP.S. Please read carefully and follow: rulesforpostingpleasereadthisbeforeposting133935.html
_________________
New to the Math Forum? Please read this: 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? Extrahard Quant Tests with Brilliant Analytics




Re: Lindsay can paint 1/x of a certain room in one hour
[#permalink]
10 Dec 2014, 04:06



Go to page
1 2
Next
[ 27 posts ]





Similar topics 
Author 
Replies 
Last post 
Similar Topics:




Kathleen can paint a room in 3 hours, and Anthony can paint an identic

Bunuel 
6 
13 Apr 2016, 22:54 

6


Cameron can paint a room in c hours. Cameron and Mackenzie, working to

gmatser1 
13 
08 Feb 2017, 13:54 

33


Lindsay can paint 1/x of a certain room in 20 minutes. What

fameatop 
7 
29 May 2017, 06:28 

71


Tom, working alone, can paint a room in 6 hours. Peter and

docabuzar 
13 
27 May 2017, 18:50 

10


Tom, working alone, can paint a room in 6 hours. Peter and

KunalPratap 
17 
20 Dec 2016, 19:49 



