It is currently 23 Feb 2018, 00:53

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

Working at constant rate, pump X pumped out half of the water in a flo

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

Hide Tags

1 KUDOS received
Intern
Intern
avatar
Joined: 23 Dec 2015
Posts: 2
Working at constant rate, pump X pumped out half of the water in a flo [#permalink]

Show Tags

New post 01 Aug 2016, 20:06
1
This post received
KUDOS
3
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

84% (00:51) correct 16% (00:38) wrong based on 274 sessions

HideShow timer Statistics

Working at constant rate, pump X pumped out half of the water in a flooded basement in 4 hours. The pump Y was started and the two pumps, working independently at their respective constant rates, pumped out rest of the water in 3 hours. How many hours would it have taken pump Y , operating alone at its own constant rate, to pump out all of the water that was pumped out of the basement?

a. 10
b. 12
c. 14
d. 18
e. 24
[Reveal] Spoiler: OA

Last edited by Bunuel on 01 Aug 2016, 23:17, edited 1 time in total.
RENAMED THE TOPIC.
1 KUDOS received
Intern
Intern
avatar
Joined: 04 May 2015
Posts: 2
Re: Working at constant rate, pump X pumped out half of the water in a flo [#permalink]

Show Tags

New post 01 Aug 2016, 22:35
1
This post received
KUDOS
1
This post was
BOOKMARKED
Here pump x was able to work 1/2 the job in 4 hrs.

so it would have taken the pump x to complete the task in 8 hrs. so 1/x=1/8.....eqn(1)

again x and y working independently doing the same work (1/2 of the work) take 3hrs.
so total task would take 6 hrs. 1/x+1/y=1/6.........eqn(2)

solve eqn 1 and eqn 2 to get y=24
Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43891
Re: Working at constant rate, pump X pumped out half of the water in a flo [#permalink]

Show Tags

New post 01 Aug 2016, 23:18
pravinpillai2015 wrote:
Working at constant rate, pump X pumped out half of the water in a flooded basement in 4 hours. The pump Y was started and the two pumps, working independently at their respective constant rates, pumped out rest of the water in 3 hours. How many hours would it have taken pump Y , operating alone at its own constant rate, to pump out all of the water that was pumped out of the basement?

a. 10
b. 12
c. 14
d. 18
e. 24


Please name topics properly. Check rule 3 here: rules-for-posting-please-read-this-before-posting-133935.html 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

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43891
Re: Working at constant rate, pump X pumped out half of the water in a flo [#permalink]

Show Tags

New post 01 Aug 2016, 23:19
Bunuel wrote:
pravinpillai2015 wrote:
Working at constant rate, pump X pumped out half of the water in a flooded basement in 4 hours. The pump Y was started and the two pumps, working independently at their respective constant rates, pumped out rest of the water in 3 hours. How many hours would it have taken pump Y , operating alone at its own constant rate, to pump out all of the water that was pumped out of the basement?

a. 10
b. 12
c. 14
d. 18
e. 24


Please name topics properly. Check rule 3 here: rules-for-posting-please-read-this-before-posting-133935.html Thank you.


Almost the same question to practice: working-alone-at-its-constant-rate-pump-x-pumped-out-of-the-water-216023.html

Hope it helps.
_________________

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

Director
Director
avatar
G
Joined: 07 Dec 2014
Posts: 907
Working at constant rate, pump X pumped out half of the water in a flo [#permalink]

Show Tags

New post 02 Aug 2016, 11:33
rate of x=1/8
rate of x+y=1/6
rate of y=1/6-1/8=1/24
24 hours
BSchool Forum Moderator
User avatar
V
Joined: 26 Feb 2016
Posts: 2082
Location: India
GPA: 3.12
Premium Member CAT Tests
Re: Working at constant rate, pump X pumped out half of the water in a flo [#permalink]

Show Tags

New post 21 Jan 2018, 12:01
pravinpillai2015 wrote:
Working at constant rate, pump X pumped out half of the water in a flooded basement in 4 hours. The pump Y was started and the two pumps, working independently at their respective constant rates, pumped out rest of the water in 3 hours. How many hours would it have taken pump Y , operating alone at its own constant rate, to pump out all of the water that was pumped out of the basement?

a. 10
b. 12
c. 14
d. 18
e. 24



If the pump X pumped out half the water in 4 hours, it will pump out the entire water in 8 hours.
Similarly, the pump Y was started and the two pumps operating together are able to pump out
the entire water in 3 hours.

Assume the total capacity of the pump to be 96 units.

So, the pump X must be pumping out 12 units/hour. Since, both the pumps working together
pump out the remainder of the water in 3 hours, their combined capacity will be 16 units/hour.
Hence, pump Y must be pumping out 4 units/hour.

Therefore, Pump Y alone will take \(\frac{96}{4}\) = 24 hours(Option E)
_________________

Stay hungry, Stay foolish

2017-2018 MBA Deadlines

Class of 2020: Rotman Thread | Schulich Thread
Class of 2019: Sauder Thread

Intern
Intern
avatar
B
Joined: 30 Nov 2017
Posts: 21
Re: Working at constant rate, pump X pumped out half of the water in a flo [#permalink]

Show Tags

New post 15 Feb 2018, 08:56
Suppose X extracts x liters/hour, while Y extracts y liters/hour
In 4 hours, X extracts 4 x liters
This is half of the basement capacity. So, total volume of water in the basement = 8x liters

After 4 hours, Y was started as well. They flush the remaining 4 x in 3 hours.

In 3 hours, X and Y combined would flush 3*(x + y)

It is given that 3*(x + y) = 4x
This gives x = 3y

Operating alone how much would Y take?

Total water = 8x
Y's capacity = y liters/hour

So, time taken by Y = 8x/y

We know x = 3y
So, x/y = 3

So, time taken by Y = 8x/y = 8*3 = 24
Re: Working at constant rate, pump X pumped out half of the water in a flo   [#permalink] 15 Feb 2018, 08:56
Display posts from previous: Sort by

Working at constant rate, pump X pumped out half of the water in a flo

  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®.