A Swimming Pool is Being Filled With Water

An empty puddle being filled with water at a constant rate takes eight hours to fill to 3/5 of its capacity. How much more fourth dimension volition it take to cease filling the pool?

(A) v hr xxx min
(B) five 60 minutes 20 min
(C) 4 hr 48 min
(D) iii 60 minutes 12 min
(E) 2 hr 40 min

Every bit puddle is filled to iii/5 of its chapters then 2/5 of its capacity is left to fill.

Since it takes eight hours to fill 3/v of the pool, then to fill 2/5 of the pool it will take \(\frac{8}{(\frac{3}{five})}*\frac{2}{5} = \frac{sixteen}{3} \ hours = 5 \ hours \ twenty \ minutes\) (because if t is the fourth dimension needed to fill the pool then \(t*\frac{three}{5}=8\) –> \(t=8*\frac{5}{3} \ hours\) –> to make full 2/5 of the pool \(8*\frac{5}{three}*\frac{2}{5}=\frac{16}{3}\) hours will be needed).

Or plug values: take the capacity of the pool to be 5 liters –> iii/v of the pool or iii liters is filled in eight hours, which gives the rate of three/8 liters per hour –> remaining ii liters volition require: \(time = \frac{task}{rate} = \frac{two}{(\frac{3}{8})} = \frac{16}{3} \ hours = v \ hours \ 20 \ minutes\).

Respond: B.

_________________

Walkabout wrote:

Here’s another approach:

Important CONCEPT: Subsequently 8 hours, 3/5 of the job is finished and ii/v of the job is remaining.

This means


the remaining part of the job is ii/three the size of the first function of the task.

Think of it this fashion:

If the pool had a capacity of 5 gallons, and so the commencement function of the job would be filling 3 gallons, and the remaining part of the job is filling ii gallons.

So, the remaining part of the job (filling ii gallons) is 2/3 the size of the first part of the job (filling 3 gallons)

And so, if information technology takes eight hours to do the first function of the job, and so the time to practice the remaining part = 2/iii of 8 hours
two/3 of 8 hours = 2/iii x 8 hours
= 16/3 hours
= 5 1/three hours
= 5 hours twenty minutes

Reply: B

Thank you,
Brent

_________________

Its B
I would use percentages to do this … piece of cake for me

3/5 work = 60% = is done in 8 hrs
remaining will be 40%( percentages are always 100) exist washed in viii*40/sixty = 16/3 = 5 1/3 hrs = 5+i/3*60 = 5.twenty hrs

PS:Edited for a typo

1st convert to mins to avoid the confusion

threescore% = 480 mins
therefore 40% (remaining) = 320 mins (using unitary method)

320 mins = 5 hrs twenty mins

I tried using only ratios to solve this (considering rate is constant):

8Hrs to fill three/5 tank i.e 0.half dozen of the tank
X hrs to fill 2/5 tank i.eastward 0.4 of the tank

=> eight/0.6 = 10/0.four
=> 10=3.2/0.half dozen = 32/half-dozen = 16/3 = 5.33hrs i.e 5hr20min

As per what I did,

8 Hours – 3/v of capacity
? Fourth dimension – to fill remaining – 2/5 of chapters.

Merely the answer I am getting is incorrect. Could someone share the appropriate process to work on this?

Hi Pretz,

In that location are a couple of different ways to approach the math in this question. It looks similar you started to set up a ratio, but didn’t consummate the work. Here’s ane fashion to become about it:

Since it takes 8 hours to fill 3/5 of the pool and X hours to make full two/5 of the pool…..

8/X = (3/v)/(2/5)

Since both fractions are “over 5”, we tin multiply those 5s out (by multiplying the numerator and denominator by 5)….

8/X = 3/two

Now we can cantankerous-multiply and solve for X….

16 = 3X
16/3 = Ten
five 1/iii hours = X

five 1/3 hours = 5 hours 20 minutes

Final Answer:

GMAT assassins aren’t built-in, they’re made,
Rich

_________________

If it takes 8 hours to fill up 3/5 of the pool, and so
information technology takes 8/3 hours to make full i/5 of the pool, and

it thus takes 16/3 hours to fill 2/5 of the pool, which is what we need to practice.

_________________

An empty pool being filled with water at a constant rate takes eight hours to fill to 3/5 of its capacity. How much more time will it take to finish filling the pool?

(iii/5) An empty pool being filled with h2o at a constant rate takes 8 hours to fill to 3/5 of its capacity. How much more fourth dimension will it take to cease filling the pool?
(three/5) of a pool/ 8 hours = 3/40 (the rate)

(three pools/40 hours) = (two/5* puddle)/ x hours

Cross multiply 3x = (2/5) forty
3x = (2/v) (eight) (five)
3x = 16
x = 16/3 or five 1/three
1/three of an hour = twenty minutes

* The puddle is 3/5 full so 2/5 remains.

(A) 5 hr 30 min
(B) five hr 20 min

(C) 4 hr 48 min
(D) three hour 12 min
(Due east) 2 hour twoscore min

Walkabout wrote:

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 aforementioned as a fourth dimension of x number of hours is to filling up (the remaining) 2/5 of the pool. Setting this up mathematically we have:

eight/(3/5) = 10/(2/5)

8/(3/5) = x/(ii/5)

40/iii= 5x/two

Cross multiplying, we get:

80 = 15x

sixteen = 3x

sixteen/3 = x

5 1/3 hours = x

5 hours and 20 minutes = x

Respond: B

_________________

GMATD11 wrote:

45-second approach: Detect rate of filling. Detect work remaining. Observe fourth dimension needed to finish: Work divided past charge per unit equals time (to fill book that needs filling).

What is charge per unit of filling?

\(\frac{Piece of work}{time} = rate\)

Rate = \(\frac{(\frac{3}{5})}{8} = (\frac{3}{v}*\frac{1}{8})= \frac{three}{twoscore}\)

How much work remaining?
\(1 – (\frac{3}{v}) = (\frac{5}{5} – \frac{3}{5})= \frac{2}{v}\)

How much time to finish remaining work?
\(\frac{Piece of work}{rate} = time\)

Work remaining = \(\frac{two}{5}\)
Charge per unit = \(\frac{3}{40}\)

\(\frac{(\frac{2}{5})}{(\frac{3}{twoscore})}\) =

\(\frac{2}{5} *
\frac{forty}{iii} = 5\frac{one}{iii}hrs\)

Multiply
any
fraction of an hour past 60 to get minutes.* In cases where you already accept the hours, and you demand hours plus minutes, utilize
merely
the fraction. (Do not include the 5 here.)

\(\frac{1}{3}hour * lx =\) 20 minutes

\(5\frac{1}{3}hrs\) = 5 hours, twenty minutes

Answer B

*Because:

\(\frac{1hr}{3} * \frac{60min}{1hr} =\) 20 minutes, where hours cancel

_________________

Hi All,

We’re told that viii hours fills iii/5 of the pool; the question asks how long it volition take to fill the remaining 2/5 of the pool. Since the pool is filling at a constant charge per unit, we tin can use a ratio to answer the question. The ratio tin can be written in a number of dissimilar means; I used:

eight/10 = (3/v)/(2/v)

Simplifying, we get…

8/X = 3/2

Now, cross-multiply…

3X = 16

X = 5 1/3 hours

Last Answer:

GMAT assassins aren’t built-in, they’re made,

Rich

_________________

GMATD11 wrote:

We can let due north = the time information technology takes to make full the remaining ii/five of the pool and create the proportion:

8/(iii/5) = north/(two/v)

twoscore/3 = 5n/2

80 = 15n

n = 80/15 = 16/3 = five 1/3 hours = 5 hours and twenty minutes

Respond: B

_________________

3/5 full in 8 hours (rest = 1-(3/v) = ii/5)
2/five is filled in (eight*five*20)/3*5 = viii 60 minutes 20 minutes

_________________

Bunuel wrote:

Let the capacity of the puddle exist \(40\) Units ( LCM of five & 8)

So, in viii Hours the pipage fills \(24\) units; Thus efficiency of the pipe is 3units/Hour

Time required to fill the entire pool is \(\frac{16}{3}\) hours = \(5\frac{1}{3} = 5 Hours twenty Min\); Reply must be (B)


_________________

3/5 of the capacity takes =eight hours
So whole chapters will take =8*(five/3)=40/iii hours
More than times needed=(40/iii)-8=sixteen/3= 5 hours 20 minutes.

Posted from my mobile device

Hello from the GMAT Guild BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, however it had no discussion for over a year. I am now bumping it up – doing my job. I call back you may notice information technology valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on contour). Y’all will receive a summary of all topics I bump in your profile area as well as via email.

_________________