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

 It is currently 20 Nov 2018, 09:47

# How to Quickly Solve GMAT Questions - Chat with ExamPAL. Join HERE!

### 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

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

## Events & Promotions

###### Events & Promotions in November
PrevNext
SuMoTuWeThFrSa
28293031123
45678910
11121314151617
18192021222324
2526272829301
Open Detailed Calendar
• ### All GMAT Club Tests are Free and open on November 22nd in celebration of Thanksgiving Day!

November 22, 2018

November 22, 2018

10:00 PM PST

11:00 PM PST

Mark your calendars - All GMAT Club Tests are free and open November 22nd to celebrate Thanksgiving Day! Access will be available from 0:01 AM to 11:59 PM, Pacific Time (USA)
• ### Free lesson on number properties

November 23, 2018

November 23, 2018

10:00 PM PST

11:00 PM PST

Practice the one most important Quant section - Integer properties, and rapidly improve your skills.

# A certain liquid passes through a drain at a rate of w/20 gallons ever

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 50711
A certain liquid passes through a drain at a rate of w/20 gallons ever  [#permalink]

### Show Tags

16 Nov 2015, 02:19
1
8
00:00

Difficulty:

55% (hard)

Question Stats:

62% (01:36) correct 38% (01:19) wrong based on 274 sessions

### HideShow timer Statistics

A certain liquid passes through a drain at a rate of w/20 gallons every x seconds. At that rate, how many minutes will it take y gallons to pass through the drain?

A. y/(1200xy)
B. 20xy/w
C. xy/(3w(
D. w/(3xy)
E. 3y/(wx)

_________________
Verbal Forum Moderator
Status: Greatness begins beyond your comfort zone
Joined: 08 Dec 2013
Posts: 2127
Location: India
Concentration: General Management, Strategy
Schools: Kelley '20, ISB '19
GPA: 3.2
WE: Information Technology (Consulting)
A certain liquid passes through a drain at a rate of w/20 gallons ever  [#permalink]

### Show Tags

Updated on: 16 Nov 2015, 03:52
1
Time needed for w/20 gallons of liquid to pass through a drain = x seconds
Time needed for w gallons of liquid to pass through a drain = 20x seconds

Time needed for y gallons of liquid to pass through a drain = (20x/w)*y = 20xy/w seconds
= (20xy/w )/60 = xy/(3w) mins

_________________

When everything seems to be going against you, remember that the airplane takes off against the wind, not with it. - Henry Ford
The Moment You Think About Giving Up, Think Of The Reason Why You Held On So Long
+1 Kudos if you find this post helpful

Originally posted by Skywalker18 on 16 Nov 2015, 02:49.
Last edited by Skywalker18 on 16 Nov 2015, 03:52, edited 2 times in total.
Director
Joined: 20 Feb 2015
Posts: 796
Concentration: Strategy, General Management
Re: A certain liquid passes through a drain at a rate of w/20 gallons ever  [#permalink]

### Show Tags

16 Nov 2015, 02:59
Can be done using unitary method.

w/20 gallons every x seconds
therefore in 1 second W/20x gallons
in 60 seconds (w/20x)*60 = 1 minute
so
3w/x gallons pass in 1 minute
1 gallon in x/3w minutes
y gallons in xy/3w minutes
Manager
Joined: 17 Aug 2015
Posts: 98
Location: India
Concentration: Strategy, General Management
Schools: Duke '19 (II)
GMAT 1: 750 Q49 V42
GPA: 4
WE: Information Technology (Investment Banking)
Re: A certain liquid passes through a drain at a rate of w/20 gallons ever  [#permalink]

### Show Tags

16 Nov 2015, 03:00
1
w/20 gallons every x seconds => w/20x gallons per second => (60w/20x) gallons per minute (we calculate this because the final answer is required to be in minutes).

So, we have

60w/20x gallons in 1 minute

y gallons in how many minutes?

Minutes = y*1 / (60w/20x) = xy/3w

Hence, (C)

Bunuel wrote:
A certain liquid passes through a drain at a rate of w/20 gallons every x seconds. At that rate, how many minutes will it take y gallons to pass through the drain?

A. y/(1200xy)
B. 20xy/w
C. xy/(3w(
D. w/(3xy)
E. 3y/(wx)

_________________

If you like this post, be kind and help me with Kudos!

Cheers!

Director
Joined: 13 Mar 2017
Posts: 632
Location: India
Concentration: General Management, Entrepreneurship
GPA: 3.8
WE: Engineering (Energy and Utilities)
Re: A certain liquid passes through a drain at a rate of w/20 gallons ever  [#permalink]

### Show Tags

09 Apr 2018, 20:54
Bunuel wrote:
A certain liquid passes through a drain at a rate of w/20 gallons every x seconds. At that rate, how many minutes will it take y gallons to pass through the drain?

A. y/(1200xy)
B. 20xy/w
C. xy/(3w(
D. w/(3xy)
E. 3y/(wx)

Rate of passing of liquid = w/20 gallons every x seconds = w/(20x) gallons per second
Time taken by y gallons to pass through the drain = y/[w/(20x)] seconds = 20xy/w seconds
in minutes = 20xy/(w*60) = xy/3w

_________________

CAT 2017 99th percentiler : VA 97.27 | DI-LR 96.84 | QA 98.04 | OA 98.95
UPSC Aspirants : Get my app UPSC Important News Reader from Play store.

MBA Social Network : WebMaggu

Appreciate by Clicking +1 Kudos ( Lets be more generous friends.)

What I believe is : "Nothing is Impossible, Even Impossible says I'm Possible" : "Stay Hungry, Stay Foolish".

e-GMAT Representative
Joined: 04 Jan 2015
Posts: 2203
Re: A certain liquid passes through a drain at a rate of w/20 gallons ever  [#permalink]

### Show Tags

09 Apr 2018, 22:38

Solution

Given:
• The liquid passes through the drain at the rate of $$\frac{w}{20}$$ gallons in every x seconds

To find:
• In how many minutes, y gallons of liquid can pass through the drain.

Approach and Working:

In every x seconds, $$\frac{w}{20}$$ gallons of liquid passes.
• In x seconds => $$\frac{w}{20}$$ gallons pass through the drain.
• Therefore, in 1 seconds= $$\frac{w}{(20x}$$ gallons pass through the drain.
• Therefore, in 1 minute=$$\frac{(w*60)}{(20*x)}$$ = $$\frac{3w}{x}$$ gallons pass through the drain.

Since $$\frac{3w}{x}$$ gallons pass through the drain in 1 minute. Then, 1 gallon will pass through the drain in:
• 1-gallon pass through the drain = $$\frac{x}{3w}$$ minutes

Hence, y gallon will pass thorough the drain in $$\frac{xy}{3w}$$minutes.

Hence, the correct answer is option C.

_________________

Number Properties | Algebra |Quant Workshop

Success Stories
Guillermo's Success Story | Carrie's Success Story

Ace GMAT quant
Articles and Question to reach Q51 | Question of the week

Number Properties – Even Odd | LCM GCD | Statistics-1 | Statistics-2
Word Problems – Percentage 1 | Percentage 2 | Time and Work 1 | Time and Work 2 | Time, Speed and Distance 1 | Time, Speed and Distance 2
Advanced Topics- Permutation and Combination 1 | Permutation and Combination 2 | Permutation and Combination 3 | Probability
Geometry- Triangles 1 | Triangles 2 | Triangles 3 | Common Mistakes in Geometry
Algebra- Wavy line | Inequalities

Practice Questions
Number Properties 1 | Number Properties 2 | Algebra 1 | Geometry | Prime Numbers | Absolute value equations | Sets

| '4 out of Top 5' Instructors on gmatclub | 70 point improvement guarantee | www.e-gmat.com

GMATH Teacher
Status: GMATH founder
Joined: 12 Oct 2010
Posts: 484
Re: A certain liquid passes through a drain at a rate of w/20 gallons ever  [#permalink]

### Show Tags

14 Sep 2018, 06:21
Bunuel wrote:
A certain liquid passes through a drain at a rate of w/20 gallons every x seconds. At that rate, how many minutes will it take y gallons to pass through the drain?

A. y/(1200xy)
B. 20xy/w
C. xy/(3w)
D. w/(3xy)
E. 3y/(wx)

Excellent opportunity to use UNITS CONTROL , one of the most powerful tools of our method!

$$\frac{{\,\,\frac{w}{{20}}\,\,}}{x}\,\,\,\frac{{{\text{gallons}}}}{{\text{s}}}\,\,\, = \,\,\,\frac{w}{{20\,\,x}}\,\,\,\frac{{{\text{gallons}}}}{{\text{s}}}$$

$$?\,\,\,\min \,\,\, \leftrightarrow \,\,\,y\,\,\,{\text{gallons}}\,$$

$$?\,\,\, = \,\,\,y\,\,{\text{gallons}}\,\,\,\left( {\frac{{\,20\,\,x\,\,{\text{s}}\,}}{{w\,\,{\text{gallons}}}}\,\,\begin{array}{*{20}{c}} \nearrow \\ \nearrow \end{array}} \right)\,\,\,\,\,\left( {\frac{{\,1\,\,\min \,}}{{60\,\,{\text{s}}}}\,\,\begin{array}{*{20}{c}} \nearrow \\ \nearrow \end{array}} \right)\,\,\,\, = \,\,\,\,\frac{{20\,\,xy}}{{60\,\,w}}\,\,\, = \,\,\,\frac{{xy}}{{\,3w\,}}\,\,\,\,\,\,\,\,\left[ {\min } \right]$$

Obs.: arrows indicate licit converters.

This solution follows the notations and rationale taught in the GMATH method.

Regards,
Fabio.
_________________

Fabio Skilnik :: https://GMATH.net (Math for the GMAT) or GMATH.com.br (Portuguese version)
Course release PROMO : finish our test drive till 30/Nov with (at least) 50 correct answers out of 92 (12-questions Mock included) to gain a 50% discount!

Intern
Status: No Progress without Struggle
Joined: 04 Aug 2017
Posts: 43
Location: Armenia
GPA: 3.4
A certain liquid passes through a drain at a rate of w/20 gallons ever  [#permalink]

### Show Tags

17 Sep 2018, 13:26
In every rate question, it's appropriate to first create the equilibrium of time -- all represent in the hour, minute, second and so forth. Then try to find the rate of this particular time:
w/60 gallon in x/60 minute or 60w/20x gallon per minute.
y:60w/20x or y:3w/x, which equals to xy/3w.
_________________

Seryozha Sargsyan 21

Contact: sargsyanseryozha@gmail.com

What you think, you become,
What you feel, you attract,
What you imagine, you create.

Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 4170
Location: United States (CA)
Re: A certain liquid passes through a drain at a rate of w/20 gallons ever  [#permalink]

### Show Tags

18 Sep 2018, 17:45
Bunuel wrote:
A certain liquid passes through a drain at a rate of w/20 gallons every x seconds. At that rate, how many minutes will it take y gallons to pass through the drain?

A. y/(1200xy)
B. 20xy/w
C. xy/(3w(
D. w/(3xy)
E. 3y/(wx)

The rate is (w/20)/x = w/(20x)

So y gallons will pass through the drain in y/(w/(20x)) = 20xy/w seconds, which is (20xy/w)/60 = 20xy/(60w) = xy/(3w) minutes

_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 12890
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: A certain liquid passes through a drain at a rate of w/20 gallons ever  [#permalink]

### Show Tags

27 Sep 2018, 19:28
Hi All,

We're told that a certain liquid passes through a drain at a rate of W/20 gallons every X SECONDS. We're asked how many MINUTES it would take Y gallons to pass through the drain. This question can be solved in a number of different ways, including by TESTing VALUES.

IF....
W=20 and X=2, then 20/20 = 1 gallon passes through every 2 seconds
Y = 30 gallons --> which would take 2(30) = 60 seconds = 1 minute
so we're looking for an answer that equals 1 when W=20, X=3 and Y=30. There's only one answer that matches....

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

Co-Founder & GMAT Assassin

Special Offer: Save \$75 + GMAT Club Tests Free
Official GMAT Exam Packs + 70 Pt. Improvement Guarantee
www.empowergmat.com/

*****Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!*****

Re: A certain liquid passes through a drain at a rate of w/20 gallons ever &nbs [#permalink] 27 Sep 2018, 19:28
Display posts from previous: Sort by