Author 
Message 
TAGS:

Hide Tags

Manager
Joined: 02 Dec 2012
Posts: 178

An empty pool being filled with water at a constant rate [#permalink]
Show Tags
20 Dec 2012, 05:53
2
This post received KUDOS
9
This post was BOOKMARKED
Question Stats:
74% (02:16) correct
26% (01:23) wrong based on 935 sessions
HideShow timer Statistics
An empty pool being filled with water at a constant rate takes 8 hours to fill to 3/5 of its capacity. How much more time will it take to finish filling the pool? (A) 5 hr 30 min (B) 5 hr 20 min (C) 4 hr 48 min (D) 3 hr 12 min (E) 2 hr 40 min
Official Answer and Stats are available only to registered users. Register/ Login.



Math Expert
Joined: 02 Sep 2009
Posts: 39728

Re: An empty pool being filled with water at a constant rate [#permalink]
Show Tags
20 Dec 2012, 05:56
Walkabout wrote: An empty pool being filled with water at a constant rate takes 8 hours to fill to 3/5 of its capacity. How much more time will it take to finish filling the pool?
(A) 5 hr 30 min (B) 5 hr 20 min (C) 4 hr 48 min (D) 3 hr 12 min (E) 2 hr 40 min As pool is filled to 3/5 of its capacity then 2/5 of its capacity is left to fill. Since it takes 8 hours to fill 3/5 of the pool, then to fill 2/5 of the pool it will take 8/(3/5)*2/5 = 16/3 hours = 5 hours 20 minutes (because if t is the time needed to fill the pool then t*3/5=8 > t=8*5/3 hours > to fill 2/5 of the pool 8*5/3*2/5=16/3 hours will be needed). Or plug values: take the capacity of the pool to be 5 liters > 3/5 of the pool or 3 liters is filled in 8 hours, which gives the rate of 3/8 liters per hour > remaining 2 liters will require: time = job/rate = 2/(3/8) = 16/3 hours = 5 hours 20 minutes. Answer: B.
_________________
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



Manager
Joined: 08 Dec 2012
Posts: 66
Location: United Kingdom
WE: Engineering (Consulting)

Re: An empty pool being filled with water at a constant rate [#permalink]
Show Tags
26 Jan 2013, 05:33
3
This post received KUDOS
2
This post was BOOKMARKED
I tried using just ratios to solve this (because rate is constant):
8Hrs to fill 3/5 tank i.e 0.6 of the tank X hrs to fill 2/5 tank i.e 0.4 of the tank
=> 8/0.6 = X/0.4 => X=3.2/0.6 = 32/6 = 16/3 = 5.33hrs i.e 5hr20min



Manager
Joined: 28 Aug 2012
Posts: 52
Concentration: Operations, Marketing
GPA: 4
WE: Information Technology (Other)

Re: An empty pool being filled with water at a constant rate [#permalink]
Show Tags
28 Jan 2013, 14:28
1
This post received KUDOS
Hey, Is'nt 16/3 = 5.3 ~ . This might be silly, but i chose 5 hours 30 mins . I don't want to make this mistake again, kindly help me Thanks Aj



Intern
Joined: 29 Dec 2011
Posts: 29

Re: An empty pool being filled with water at a constant rate [#permalink]
Show Tags
28 Jan 2013, 15:11
1
This post received KUDOS
1
This post was BOOKMARKED
30 minutes/60 minutes=.5, so 5 and a half hours would be 5.5, not 5.33.



GMAT Club Legend
Joined: 09 Sep 2013
Posts: 16015

Re: An empty pool being filled with water at a constant rate [#permalink]
Show Tags
26 Apr 2014, 19:12
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 Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



Intern
Joined: 21 Feb 2014
Posts: 1

Re: An empty pool being filled with water at a constant rate [#permalink]
Show Tags
21 May 2015, 04:55
Let the total amount of water eq l
then rate : ( 3/5 * l ) / 8 = 3/40 * l
So time required to fill the full tank = l / ( (3/40) * l ) = 40/3
So time required to fill the remaining section = ( 40/3  8 ) hrs = 16/3 hrs = 5 1/3 hrs = 5 hr 20 min



Intern
Joined: 30 Jul 2013
Posts: 43
Concentration: Technology, General Management
GMAT Date: 07032015
GPA: 3.8
WE: Information Technology (Computer Software)

Re: An empty pool being filled with water at a constant rate takes 8 hours [#permalink]
Show Tags
29 May 2015, 21:03
As per what I did, 8 Hours  3/5 of capacity ? Time  to fill remaining  2/5 of capacity. But the answer I am getting is incorrect. Could someone share the appropriate process to work on this?
_________________
On the Kudos Spree.
If you like my post/comment please appreciate with kudos



EMPOWERgmat Instructor
Status: GMAT Assassin/CoFounder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 9289
Location: United States (CA)
GRE 1: 340 Q170 V170

Re: An empty pool being filled with water at a constant rate takes 8 hours [#permalink]
Show Tags
29 May 2015, 21:08
Hi Pretz, There are a couple of different ways to approach the math in this question. It looks like you started to set up a ratio, but didn't complete the work. Here's one way to go about it: Since it takes 8 hours to fill 3/5 of the pool and X hours to fill 2/5 of the pool..... 8/X = (3/5)/(2/5) Since both fractions are "over 5", we can multiply those 5s out (by multiplying the numerator and denominator by 5).... 8/X = 3/2 Now we can crossmultiply and solve for X.... 16 = 3X 16/3 = X 5 1/3 hours = X 5 1/3 hours = 5 hours 20 minutes Final Answer: GMAT assassins aren't born, they're made, Rich
_________________
760+: Learn What GMAT Assassins Do to Score at the Highest Levels Contact Rich at: Rich.C@empowergmat.com
Rich Cohen
CoFounder & GMAT Assassin
***********************Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!***********************



Manager
Joined: 21 Feb 2012
Posts: 61

An empty pool being filled with water at a constant rate takes 8 hours [#permalink]
Show Tags
29 May 2015, 21:46
Pretz wrote: As per what I did,
8 Hours  3/5 of capacity ? Time  to fill remaining  2/5 of capacity.
But the answer I am getting is incorrect. Could someone share the appropriate process to work on this? Hello there PretzI think your approach is fine. \(8\) \(hours\)  \(\frac{3}{5}\) multiply by \(\frac{5}{3}\) on both sides \(8*\frac{5}{3}\) \(hours\)  \(\frac{3}{5} *\frac{5}{3}\) \(\frac{40}{3}\) \(hours\)  \(1\) So it takes \(\frac{40}{3}\) \(hours\) to fill the tank The additional time required to fill \(\frac{2}{3}\)rd of the tank will be \(\frac{40}{3}  8\) \(hours\) \(\frac{16}{3}\) \(hours\) \(5 \frac{1}{3}\) \(hours\) \(5\) \(hours\) \(20\) \(minutes\) I hope that explains it
_________________
Regards J
Do consider a Kudos if you find the post useful



GMAT Tutor
Joined: 24 Jun 2008
Posts: 1179

Re: An empty pool being filled with water at a constant rate takes 8 hours [#permalink]
Show Tags
29 May 2015, 21:53
If it takes 8 hours to fill 3/5 of the pool, then it takes 8/3 hours to fill 1/5 of the pool, and it thus takes 16/3 hours to fill 2/5 of the pool, which is what we need to do.
_________________
GMAT Tutor in Toronto
If you are looking for online GMAT math tutoring, or if you are interested in buying my advanced Quant books and problem sets, please contact me at ianstewartgmat at gmail.com



Intern
Joined: 30 Jul 2013
Posts: 43
Concentration: Technology, General Management
GMAT Date: 07032015
GPA: 3.8
WE: Information Technology (Computer Software)

Re: An empty pool being filled with water at a constant rate takes 8 hours [#permalink]
Show Tags
29 May 2015, 22:05
Awesome! Thank you so much all!
_________________
On the Kudos Spree.
If you like my post/comment please appreciate with kudos



Senior Manager
Joined: 21 May 2015
Posts: 271
Concentration: Operations, Strategy

Re: An empty pool being filled with water at a constant rate [#permalink]
Show Tags
01 Jun 2015, 02:53
B if the rates are constant the ratio of capacity is proportional to that of time x/8=2/3  x = 5 hr 20 min
_________________
Apoorv
I realize that i cannot change the world....But i can play a part



Optimus Prep Instructor
Joined: 06 Nov 2014
Posts: 1845

Re: An empty pool being filled with water at a constant rate [#permalink]
Show Tags
02 Jun 2015, 09:13
An empty pool being filled with water at a constant rate takes 8 hours to fill to 3/5 of its capacity. How much more time will it take to finish filling the pool? (3/5) An empty pool being filled with water at a constant rate takes 8 hours to fill to 3/5 of its capacity. How much more time will it take to finish filling the pool? (3/5) of a pool/ 8 hours = 3/40 (the rate) (3 pools/40 hours) = (2/5* pool)/ x hours Cross multiply 3x = (2/5) 40 3x = (2/ 5) (8) ( 5) 3x = 16 x = 16/3 or 5 1/3 1/3 of an hour = 20 minutes * The pool is 3/5 full so 2/5 remains. (A) 5 hr 30 min (B) 5 hr 20 min(C) 4 hr 48 min (D) 3 hr 12 min (E) 2 hr 40 min
_________________
Janielle Williams
Customer Support



Manager
Joined: 20 Mar 2015
Posts: 69

Re: An empty pool being filled with water at a constant rate [#permalink]
Show Tags
17 May 2016, 05:59
1
This post was BOOKMARKED
We know, R * T = Q , suppose the Q=100ltr. then, R * 8 = 3/5 of 100 ==> 60/8 ==> 15/2 ltr per hour.
now, remaning 40ltr(which is 100  60 or 2/5 of 100) R * t = Q or, 15/2 * t = 40 or, t = 40 * 2/15 t = 16/3 = 5.33 = 5 hour + 1/3 and 1/3 of 60 = 20. so, 5 hour 20 mins.
If only such questions were asked in GMAT.



Target Test Prep Representative
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 1082

Re: An empty pool being filled with water at a constant rate [#permalink]
Show Tags
17 May 2016, 17:01
Walkabout wrote: An empty pool being filled with water at a constant rate takes 8 hours to fill to 3/5 of its capacity. How much more time will it take to finish filling the pool?
(A) 5 hr 30 min (B) 5 hr 20 min (C) 4 hr 48 min (D) 3 hr 12 min (E) 2 hr 40 min Solution: To solve we can setup a proportion. The proportion will read: A time of 8 hours is to filling up 3/5 of the pool is the same as a time of x number of hours is to filling up (the remaining) 2/5 of the pool. Setting this up mathematically we have: 8/(3/5) = x/(2/5) 8/(3/5) = x/(2/5) 40/3= 5x/2 Cross multiplying, we get: 80 = 15x 16 = 3x 16/3 = x 5 1/3 hours = x 5 hours and 20 minutes = x Answer: B
_________________
Jeffery Miller
Head of GMAT Instruction
GMAT Quant SelfStudy Course
500+ lessons 3000+ practice problems 800+ HD solutions



GMAT Club Legend
Joined: 09 Sep 2013
Posts: 16015

Re: An empty pool being filled with water at a constant rate [#permalink]
Show Tags
23 May 2017, 20:36
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 Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources




Re: An empty pool being filled with water at a constant rate
[#permalink]
23 May 2017, 20:36







