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

 It is currently 19 Jan 2019, 15:13

### 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 January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
• ### FREE Quant Workshop by e-GMAT!

January 20, 2019

January 20, 2019

07:00 AM PST

07:00 AM PST

Get personalized insights on how to achieve your Target Quant Score.
• ### Free GMAT Strategy Webinar

January 19, 2019

January 19, 2019

07:00 AM PST

09:00 AM PST

Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

# The Malibu Country Club needs to drain its pool for refinishing. The h

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 52294
The Malibu Country Club needs to drain its pool for refinishing. The h  [#permalink]

### Show Tags

06 Feb 2015, 06:42
00:00

Difficulty:

35% (medium)

Question Stats:

77% (02:12) correct 23% (02:14) wrong based on 400 sessions

### HideShow timer Statistics

The Malibu Country Club needs to drain its pool for refinishing. The hose they use to drain it can remove 60 cubic feet of water per minute. If the pool is 80 feet wide by 150 feet long by 10 feet deep and is currently at 80% capacity, how long will it take to drain the pool?

A. 24 hours
B. 26 2/3 hours
C. 30 hours
D. 33 1/3 hours
E. 160 hours

Kudos for a correct solution.

_________________
Manager
Joined: 04 Oct 2013
Posts: 169
GMAT 1: 590 Q40 V30
GMAT 2: 730 Q49 V40
WE: Project Management (Entertainment and Sports)
Re: The Malibu Country Club needs to drain its pool for refinishing. The h  [#permalink]

### Show Tags

Updated on: 06 Feb 2015, 11:25
1
Bunuel wrote:
The Malibu Country Club needs to drain its pool for refinishing. The hose they use to drain it can remove 60 cubic feet of water per minute. If the pool is 80 feet wide by 150 feet long by 10 feet deep and is currently at 80% capacity, how long will it take to drain the pool?

A. 24 hours
B. 26 2/3 hours
C. 30 hours
D. 33 1/3 hours
E. 160 hours

Kudos for a correct solution.

Pool's volume=80(150)10. Pool's current capacity=96000 $$f^3$$. If the hose can remove 60 $$f^3$$/m it will take 1600 minutes to drain the pool at the actual capacity. 1600 minutes are 26 2/3 hours.

_________________

learn the rules of the game, then play better than anyone else.

Originally posted by gmat6nplus1 on 06 Feb 2015, 07:28.
Last edited by gmat6nplus1 on 06 Feb 2015, 11:25, edited 1 time in total.
Math Expert
Joined: 02 Sep 2009
Posts: 52294
Re: The Malibu Country Club needs to drain its pool for refinishing. The h  [#permalink]

### Show Tags

09 Feb 2015, 05:05
Bunuel wrote:
The Malibu Country Club needs to drain its pool for refinishing. The hose they use to drain it can remove 60 cubic feet of water per minute. If the pool is 80 feet wide by 150 feet long by 10 feet deep and is currently at 80% capacity, how long will it take to drain the pool?

A. 24 hours
B. 26 2/3 hours
C. 30 hours
D. 33 1/3 hours
E. 160 hours

Kudos for a correct solution.

VERITAS PREP OFFICIAL SOLUTION:

To determine how long the hose will take to drain the pool, you must first determine how much water needs to be drained. From there, you would calculate how many minutes it would take to drain that amount of water, and noting that your answer choices are all in terms of hours, you would convert that to hours. In order to minimize the calculations and time spent, you are best served doing all the calculations in one step, so you can go through and reduce as much as possible before performing the actual math. Your calculations would look like:

(80 x 150 x 10 (cubic feet)) x (8)/10 (equivalent of 80%) x (1 minutes)/(60 cubic ft) x (1 hour)/(60 minutes)
Once reduced, this becomes simply (8x5x2)/3, or 80/3 hours, which is 26 and 2/3 hours.
_________________
Director
Joined: 24 Nov 2015
Posts: 515
Location: United States (LA)
Re: The Malibu Country Club needs to drain its pool for refinishing. The h  [#permalink]

### Show Tags

25 Apr 2016, 07:19
volume of pool = 150 * 80 * 10 = 120000 cubic feet
80% of full capacity of pool = 8/10 * 120000 = 96000 cubic feet
rate at which the pool is draining = 60 cubic feet / minute
rate of draining in minutes = 96000 / 60 = 1600 minutes
1600 minutes = 26 hrs 40 minutes
VP
Status: It's near - I can see.
Joined: 13 Apr 2013
Posts: 1364
Location: India
GMAT 1: 480 Q38 V22
GPA: 3.01
WE: Engineering (Consulting)
Re: The Malibu Country Club needs to drain its pool for refinishing. The h  [#permalink]

### Show Tags

10 May 2018, 22:56
Bunuel wrote:
The Malibu Country Club needs to drain its pool for refinishing. The hose they use to drain it can remove 60 cubic feet of water per minute. If the pool is 80 feet wide by 150 feet long by 10 feet deep and is currently at 80% capacity, how long will it take to drain the pool?

A. 24 hours
B. 26 2/3 hours
C. 30 hours
D. 33 1/3 hours
E. 160 hours

Rate of draining = 60 cubic/feet

Volume of water in pool = 80*150*10*0.8

Time taken to empty the pool = (80*150*10*0.8)/60

= 1600 minutes or 1600/60

= 26.66 hrs (B)

_________________

"Do not watch clock; Do what it does. KEEP GOING."

Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 4551
Location: United States (CA)
Re: The Malibu Country Club needs to drain its pool for refinishing. The h  [#permalink]

### Show Tags

14 May 2018, 15:51
Bunuel wrote:
The Malibu Country Club needs to drain its pool for refinishing. The hose they use to drain it can remove 60 cubic feet of water per minute. If the pool is 80 feet wide by 150 feet long by 10 feet deep and is currently at 80% capacity, how long will it take to drain the pool?

A. 24 hours
B. 26 2/3 hours
C. 30 hours
D. 33 1/3 hours
E. 160 hours

The amount of water that needs to be drained is:

80 x 150 x 10 x 4/5 = 80 x 150 x 8 = 96,000 ft^3

It will take 96,000/60 = 9600/6 = 1600 minutes or 1600/60 = 80/3 = = 26 2/3 hours to drain the pool.

_________________

Scott Woodbury-Stewart
Founder and CEO

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

Manager
Joined: 20 Jun 2017
Posts: 92
GMAT 1: 570 Q49 V19
The Malibu Country Club needs to drain its pool for refinishing. The h  [#permalink]

### Show Tags

15 Sep 2018, 02:51
Quote:
The Malibu Country Club needs to drain its pool for refinishing. The hose they use to drain it can remove 60 cubic feet of water per minute. If the pool is 80 feet wide by 150 feet long by 10 feet deep and is currently at 80% capacity, how long will it take to drain the pool?

A. 24 hours
B. 26 2/3 hours
C. 30 hours
D. 33 1/3 hours
E. 160 hours

Volume of water that the pool can hold = (80ft)(150ft)(10ft) = 120000$$ft^{3}$$
Pool is filled to 80% of its current capacity, hence volume of water present in the pool currently = (0.8)(120000$$ft^{3}$$) = 96000$$ft^{3}$$
rate at which hose can drain the pool = 60$$ft^{3}$$ per minute
amount of water that can be drained out in 60 minutes i.e. 1 hr = (60$$ft^{3}$$)(60) = 3600$$ft^{3}$$
3600$$ft^{3}$$ water can be drained out in 1 hr
1$$ft^{3}$$ of water can be drained out in $$\frac{1}{3600}$$ hrs
96000$$ft^{3}$$ of water can be drained out in $$\frac{96000}{3600}$$ hrs = $$\frac{80}{3}$$ hrs
GMATH Teacher
Status: GMATH founder
Joined: 12 Oct 2010
Posts: 619
Re: The Malibu Country Club needs to drain its pool for refinishing. The h  [#permalink]

### Show Tags

15 Sep 2018, 16:56
Bunuel wrote:
The Malibu Country Club needs to drain its pool for refinishing. The hose they use to drain it can remove 60 cubic feet of water per minute. If the pool is 80 feet wide by 150 feet long by 10 feet deep and is currently at 80% capacity, how long will it take to drain the pool?

A. 24 hours
B. 26 2/3 hours
C. 30 hours
D. 33 1/3 hours
E. 160 hours

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

$$\frac{{60\,\,{\text{f}}{{\text{t}}^3}}}{{1\,\,\min }}$$

$$\frac{4}{5}\left( {80 \cdot 150 \cdot 10} \right)\,\,\,{\text{f}}{{\text{t}}^3}\,\,\,\,\, \leftrightarrow \,\,\,\,?\,\,{\text{h}}$$

$$?\,\,\, = \,\,\,\frac{4}{5}\left( {80 \cdot 150 \cdot 10} \right)\,\,\,{\text{f}}{{\text{t}}^3}\,\,\,\left( {\frac{{1\,\,\min }}{{60\,\,{\text{f}}{{\text{t}}^3}}}\,\,\begin{array}{*{20}{c}} \nearrow \\ \nearrow \end{array}} \right)\,\,\,\left( {\frac{{1\,\,{\text{h}}}}{{60\,\,\min }}\,\,\begin{array}{*{20}{c}} \nearrow \\ \nearrow \end{array}} \right)$$

Obs.: arrows indicate licit converters.

$$? = \,\,\underleftrightarrow {\frac{{4 \cdot 80 \cdot 150 \cdot 10}}{{5 \cdot 60 \cdot 60}}}\,\, = \,\,\frac{{4 \cdot 8 \cdot 30}}{{6 \cdot 6}} = \frac{{80}}{3} = \frac{{60 + 18 + 2}}{3} = 26\frac{2}{3}\,\,{\text{h}}$$

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

Regards,
Fabio.
_________________

Fabio Skilnik :: GMATH method creator (Math for the GMAT)
Our high-level "quant" preparation starts here: https://gmath.net

EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 13346
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: The Malibu Country Club needs to drain its pool for refinishing. The h  [#permalink]

### Show Tags

23 Sep 2018, 10:40
Hi All,

We're told that a The Malibu Country Club needs to drain its pool for refinishing. The hose they use to drain it can remove 60 cubic feet of water per MINUTE, the pool is 80 feet wide by 150 feet long by 10 feet deep and is currently at 80% full. We're asked how long it will, in HOURS, to drain the pool. This question is essentially a big 'rate' question, but the answer choices are sufficiently 'spread out' that you can take advantage of them and avoid doing a gigantic calculation.

To start, the current amount of water in the pool is (80)(150)(10)(.8) cubic feet. While that is a lengthy calculation, here's how you can make it easier...

Since we're multiplying 4 numbers together, it does NOT matter what order we do the multiplying... Thus, we can start with (80)(.8) = 64.

(64)(150)(10) = cubic feet of water

The rate of the hose is 60 cubic feet per MINUTE. Notice how 64 is just a bit bigger than 60. Thus, it will take a little more than (150)(10) = 1500 minutes to empty the pool. 1500/60 = 150/6 = 25 hours. Thus, we need answer that is a bit bigger than 25 hours. 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: The Malibu Country Club needs to drain its pool for refinishing. The h &nbs [#permalink] 23 Sep 2018, 10:40
Display posts from previous: Sort by