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

Question

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.

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

gmat6nplus1 · Answer

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.

Answer B.

Bunuel · Answer

VERITAS PREP OFFICIAL SOLUTION:

Answer: (B)

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.

rhine29388 · Answer

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 
correct answer option B

AkshdeepS · Answer

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)

ScottTargetTestPrep · Answer

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.

Answer: B

pkshankar · Answer

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

fskilnik · Answer

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

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

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

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

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}\,\,{	ext{h}}

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

Regards, 
Fabio.

EMPOWERgmatRichC · Answer

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.

Final Answer:  B

GMAT assassins aren't born, they're made, 
Rich

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

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