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

 It is currently 17 Oct 2019, 05:58

### 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

# Pipe P can drain the liquid from a tank in 3/4 the time that

Author Message
TAGS:

### Hide Tags

Manager
Joined: 25 May 2006
Posts: 174
Pipe P can drain the liquid from a tank in 3/4 the time that  [#permalink]

### Show Tags

Updated on: 02 Jul 2014, 06:34
3
22
00:00

Difficulty:

95% (hard)

Question Stats:

59% (03:10) correct 41% (02:56) wrong based on 361 sessions

### HideShow timer Statistics

Pipe P can drain the liquid from a tank in 3/4 the time that it takes pipe Q to drain it and in 2/3 the time that it takes pipe R to do it. If all 3 pipes operating simultaneously but independently are used to drain liquid from the tank, then pipe Q drains what portion of the liquid from the tank?

A. 9/29
B. 8/23
C. 3/8
D. 17/29
E. 3/4

_________________
Who is John Galt?

Originally posted by XxxyyY on 17 Jun 2006, 19:32.
Last edited by Bunuel on 02 Jul 2014, 06:34, edited 2 times in total.
Edited the question and added the OA.
Manager
Joined: 09 May 2006
Posts: 77
Location: Bangalore, India
Re: Pipe P can drain the liquid from a tank in 3/4 the time that  [#permalink]

### Show Tags

17 Jun 2006, 20:35
6
3
A - 9/29

Plugging numbers

P-6hrs
Q-8hrs
R-9hrs

Together in one hr they can drain = 1/6+1/8+1/9 = 29/72 tank

thus together they can drain tank in 72/29 hrs

in 1 hr q drains 1/8 tank
in 72/29 hrs - 72/29*(1/8) = 9/29
##### General Discussion
Manager
Joined: 25 May 2006
Posts: 174
Re: Pipe P can drain the liquid from a tank in 3/4 the time that  [#permalink]

### Show Tags

17 Jun 2006, 20:45
You got it, Thanks. Apreciate your explanation.

Cheers
_________________
Who is John Galt?
Intern
Joined: 14 May 2014
Posts: 13
GMAT 1: 760 Q50 V42
Re: Pipe P can drain the liquid from a tank in 3/4 the time that  [#permalink]

### Show Tags

02 Jul 2014, 12:17
X & Y wrote:
Pipe P can drain the liquid from a tank in 3/4 the time that it takes pipe Q to drain it and in 2/3 the time that it takes pipe R to do it. If all 3 pipes operating simultaneously but independently are used to drain liquid from the tank, then pipe Q drains what portion of the liquid from the tank?

A. 9/29
B. 8/23
C. 3/8
D. 17/29
E. 3/4

Suppose Q can drain in 1 hr. So, rQ = 1/1 = 1
So, rP = 1/[(3/4)rQ] = 4/3
Also, rP = rR/(2/3) => 4/3 = rR/(2/3) => rR = 8/9

Let H is the time it takes to drain by running all 3 pipes simultaneously
So combined rate = rC = 1/H = 1 + 4/3 + 8/9 = 29/9 = 1/(9/29)

Thus running simultaneously, Pipe Q will drain 9/29 of the liquid.

Intern
Status: Do or Die!!
Joined: 29 Jul 2013
Posts: 9
Location: India
Concentration: Technology
GMAT 1: 630 Q49 V27
GPA: 3.86
WE: Information Technology (Computer Software)
Re: Pipe P can drain the liquid from a tank in 3/4 the time that  [#permalink]

### Show Tags

06 Jul 2014, 17:53
1
2
Bunuel wrote:
gautamodi wrote:
is the OA A or D???

Even i got it as A=9/29

It's A. Edited. Thank you.

Hi Bunuel,

I got the answer by following steps below:
R : P : Q
2 : 3
4 : 3
combined ratios can be obtained as: 8:12:9
So Q's part is 9/29 of total

Is this the correct way of solving?
Math Expert
Joined: 02 Sep 2009
Posts: 58416
Re: Pipe P can drain the liquid from a tank in 3/4 the time that  [#permalink]

### Show Tags

07 Jul 2014, 05:03
sandeep1756 wrote:
Bunuel wrote:
gautamodi wrote:
Pipe P can drain the liquid from a tank in 3/4 the time that it takes pipe Q to drain it and in 2/3 the time that it takes pipe R to do it. If all 3 pipes operating simultaneously but independently are used to drain liquid from the tank, then pipe Q drains what portion of the liquid from the tank?

A. 9/29
B. 8/23
C. 3/8
D. 17/29
E. 3/4

is the OA A or D???

Even i got it as A=9/29

It's A. Edited. Thank you.

Hi Bunuel,

I got the answer by following steps below:
R : P : Q
2 : 3
4 : 3
combined ratios can be obtained as: 8:12:9
So Q's part is 9/29 of total

Is this the correct way of solving?

Yes. That's correct.
_________________
Intern
Joined: 06 Jun 2014
Posts: 41
Pipe P can drain the liquid from a tank in 3/4 the time that  [#permalink]

### Show Tags

27 Apr 2015, 15:37
sandeep1756 wrote:
Bunuel wrote:
gautamodi wrote:
Pipe P can drain the liquid from a tank in 3/4 the time that it takes pipe Q to drain it and in 2/3 the time that it takes pipe R to do it. If all 3 pipes operating simultaneously but independently are used to drain liquid from the tank, then pipe Q drains what portion of the liquid from the tank?

A. 9/29
B. 8/23
C. 3/8
D. 17/29
E. 3/4

is the OA A or D???

Even i got it as A=9/29

It's A. Edited. Thank you.

Hi Bunuel,

I got the answer by following steps below:
R : P : Q
2 : 3
4 : 3

combined ratios can be obtained as: 8:12:9
So Q's part is 9/29 of total

Is this the correct way of solving?

I'm doubting if the ratios are correct. trying to figure out how the ratios are seted up, the problem says " P can drain the liquid from a tank in 3/4 the time that it takes pipe Q to drain it and in 2/3 the time that it takes pipe R to do it." or P=(3/4)xQ => P:Q = 3:4 not 4:3 as stated above in red. same thing for the other ratio P=(2/3)xR => P:R = 2:3
now if we even out P to be 6 ( for 2 and 3) we get P:Q:R = 6:8:9 and Q part will be 8/(8+6+9) = 8/23 which is not correct answer.
Am I missing something or what is wrong here, what do you think Bunuel and sandeep1756
e-GMAT Representative
Joined: 04 Jan 2015
Posts: 3074
Re: Pipe P can drain the liquid from a tank in 3/4 the time that  [#permalink]

### Show Tags

29 Apr 2015, 04:11
2
1
Quote:
I'm doubting if the ratios are correct. trying to figure out how the ratios are seted up, the problem says " P can drain the liquid from a tank in 3/4 the time that it takes pipe Q to drain it and in 2/3 the time that it takes pipe R to do it." or P=(3/4)xQ => P:Q = 3:4 not 4:3 as stated above in red. same thing for the other ratio P=(2/3)xR => P:R = 2:3
now if we even out P to be 6 ( for 2 and 3) we get P:Q:R = 6:8:9 and Q part will be 8/(8+6+9) = 8/23 which is not correct answer.
Am I missing something or what is wrong here, what do you think Bunuel and sandeep1756

Hi kzivrev,

The question gives us the ratio of time taken by Pipes P, Q and R to do a particular work i.e. draining the tank. We know from the time work equation that Work = Rate * Time. So rate is inversely proportional to the time taken.

So if the time taken are in the ratio of 2:1 the rates will be in the ratio of 1:2. For example if John can make 6 sandwiches in an hour and Mike can make 6 sandwiches in half an hour the ratio of time taken by John and Mike is 2:1 and hence the ratio of their rates would be 1:2 i.e Mike can make sandwiches twice as fast as John.

Coming back to the question, if all the 3 pipes work simultaneously, they would be working for the same amount of time.Hence to find the proportion of work done by pipe Q we need to find the ratios of rates of pipes P, Q and R.

Since the ratio of time taken by pipes P & Q to do a particular work is 3:4, the ratio of their rates would be 4:3. On the same lines, if the ratio of time taken by pipes P & R to do a particular work is 2:3, the ratio of their rates would be 3:2.

Hence if we assume the rate of pipe P as $$x$$, we can write the rate of pipe Q as $$\frac{3x}{4}$$ and rate of pipe R as $$\frac{2x}{3}$$. The proportion of work done by pipe Q can be calculated as rate of pipe Q divided by the total rates of pipe P, Q and R.

The sum of the rates of pipes P, Q and R is $$\frac{29x}{12}$$. Hence the proportion of work done by pipe Q would be $$\frac{3x * 12}{4 * 29x} = \frac{9}{29}$$.

Hope its clear

Regards
Harsh
_________________
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8085
Location: United States (CA)
Re: Pipe P can drain the liquid from a tank in 3/4 the time that  [#permalink]

### Show Tags

14 Feb 2018, 11:00
X & Y wrote:
Pipe P can drain the liquid from a tank in 3/4 the time that it takes pipe Q to drain it and in 2/3 the time that it takes pipe R to do it. If all 3 pipes operating simultaneously but independently are used to drain liquid from the tank, then pipe Q drains what portion of the liquid from the tank?

A. 9/29
B. 8/23
C. 3/8
D. 17/29
E. 3/4

We can let p = the time it takes pipe P to drain the liquid from the tank. Thus, the rate of pipe P = 1/p.

Since pipe P can drain the liquid from the tank in 3/4 the time that it takes pipe Q to drain it, the rate of pipe Q is:

(3/4)(1/p) = 3/(4p)

Since pipe P can drain the liquid from the tank in 2/3 the time that it takes pipe R to do it, the rate of pipe R is:

(2/3)(1/p) = 2/(3p)

Thus, the portion of liquid pipe Q drains is:

[3/(4p)] / [1/p + 3/(4p) + 2/(3p)]

Multiplying the numerator and denominator by 12p, we have:

9/(12 + 9 + 8)

9/29

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

VP
Joined: 07 Dec 2014
Posts: 1222
Re: Pipe P can drain the liquid from a tank in 3/4 the time that  [#permalink]

### Show Tags

14 Feb 2018, 23:33
X & Y wrote:
Pipe P can drain the liquid from a tank in 3/4 the time that it takes pipe Q to drain it and in 2/3 the time that it takes pipe R to do it. If all 3 pipes operating simultaneously but independently are used to drain liquid from the tank, then pipe Q drains what portion of the liquid from the tank?

A. 9/29
B. 8/23
C. 3/8
D. 17/29
E. 3/4

relative times & rates are:
P: 6/8 & 96/72
Q: 8/8 & 72/72
R: 9/8 & 64/72
combined rate=232/72
portion drained by Q=(72/72)/(232/72)=9/29
A
Senior Manager
Joined: 02 Apr 2014
Posts: 468
Location: India
Schools: XLRI"20
GMAT 1: 700 Q50 V34
GPA: 3.5
Re: Pipe P can drain the liquid from a tank in 3/4 the time that  [#permalink]

### Show Tags

22 Feb 2018, 11:50
P - rate of P, Q - rate of Q, R - rate of R
P = 4/3Q (as P takes 3/4 th time of Q)
P = 3/2R (as P takes 2/3 th time of R) => R = 8/9Q
P : Q : R = 4/3 : 1 : 8/9 = 12 : 9 : 8
Q's portion = 9/(12+9+8) = 9/29
Intern
Joined: 28 Mar 2018
Posts: 45
Re: Pipe P can drain the liquid from a tank in 3/4 the time that  [#permalink]

### Show Tags

06 Apr 2018, 11:53
hellosanthosh2k2 wrote:
P - rate of P, Q - rate of Q, R - rate of R
P = 4/3Q (as P takes 3/4 th time of Q)
P = 3/2R (as P takes 2/3 th time of R) => R = 8/9Q
P : Q : R = 4/3 : 1 : 8/9 = 12 : 9 : 8
Q's portion = 9/(12+9+8) = 9/29

I was able to solve through until I got to the highlighted portion, is someone able to explain how to go from R= 8/9Q to this three part ratio?

Math is hard
Re: Pipe P can drain the liquid from a tank in 3/4 the time that   [#permalink] 06 Apr 2018, 11:53
Display posts from previous: Sort by