Last visit was: 23 Apr 2026, 12:14 It is currently 23 Apr 2026, 12:14
Home
Messages
Tests
Schools
Events
Close
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
Your Progress

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
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
User avatar
cleetus
User avatar
Joined: 25 Jan 2010
Last visit: 01 Oct 2015
Posts: 91
Own Kudos:
800
 [43]
Given Kudos: 40
Location: Calicut, India
Concentration: Finance
Posts: 91
Kudos: 800
 [43]
A, B, C are three taps connected to a tank such that 6 times 10 Nov 2010, 10:39
7
Kudos
Add Kudos
36
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

95% (hard)

Question Stats:

53% (03:34) correct 47% (03:29) wrong based on 133 sessions

History

Date
Time
Result
Not Attempted Yet
A, B, C are three taps connected to a tank such that 6 times the time taken by A to fill the tank is 7 times the time taken by B and C together to fill the tank. 3 times the time taken by C to fill the tank is 10 times the time taken by A and B together to fill the tank. If A, B and C together fill the tank in 60/13 hours, then find the time taken by B alone to fill the tank?

A) 10 hrs
B) 15 hrs
C) 20 hrs
D) 25 hrs
E) 30 hrs
ShowHide Answer
Official Answer
B
Most Helpful Reply
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,783
Own Kudos:
810,841
 [14]
Given Kudos: 105,853
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,783
Kudos: 810,841
 [14]
A, B, C are three taps connected to a tank such that 6 times 10 Nov 2010, 11:23
9
Kudos
Add Kudos
5
Bookmarks
Bookmark this Post
cleetus
A, B, C are three taps connected to a tank such that 6 times the time taken by A to fill the tank is 7 times the time taken by B and C together to fill the tank. 3 times the time taken by C to fill the tank is 10 times the time taken by A and B together to fill the tank. If A, B and C together fill the tank in 60/13 hours, then find the time taken by B alone to fill the tank?

A) 10 hrs
B) 15 hrs
C) 20 hrs
D) 25 hrs
E) 30 hrs
Show more

Check this: word-translations-rates-work-104208.html?hilit=time%20work#p812628

Let a, b and c be the time needed for A, B and C respectively to fill the tank alone.

Given:
\(\frac{7}{6}*\frac{1}{a}=\frac{1}{b}+\frac{1}{c}\) - combined rate of B and C is 7/6 of rate of A;

\(\frac{10}{3}*\frac{1}{c}=\frac{1}{a}+\frac{1}{b}\) - combined rate of A and B is 10/3 of rate of C;

\(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}=\frac{13}{60}\) - combined rate of A, B and C is 13/60 tank/hour;

Solving:
\(\frac{1}{a}+\frac{7}{6a}=\frac{13}{60}\) --> \(a=10\);

\(\frac{1}{c}+\frac{10}{3c}=\frac{13}{60}\) --> \(c=20\);

\(\frac{1}{10}+\frac{1}{b}+\frac{1}{20}=\frac{13}{60}\) --> \(b=15\).

Answer: B.
General Discussion
avatar
pauc
avatar
Joined: 15 Sep 2013
Last visit: 03 Apr 2017
Posts: 10
Own Kudos:
8
Given Kudos: 19
Schools: Sloan '19 (A$)
GMAT 1: 700 Q46 V40
Products:
My Reviews
Schools: Sloan '19 (A$)
GMAT 1: 700 Q46 V40
Posts: 10
Kudos: 8
A, B, C are three taps connected to a tank such that 6 times 23 Oct 2013, 05:35
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
cleetus
A, B, C are three taps connected to a tank such that 6 times the time taken by A to fill the tank is 7 times the time taken by B and C together to fill the tank. 3 times the time taken by C to fill the tank is 10 times the time taken by A and B together to fill the tank. If A, B and C together fill the tank in 60/13 hours, then find the time taken by B alone to fill the tank?

A) 10 hrs
B) 15 hrs
C) 20 hrs
D) 25 hrs
E) 30 hrs

Check this: word-translations-rates-work-104208.html?hilit=time%20work#p812628

Let a, b and c be the time needed for A, B and C respectively to fill the tank alone.

Given:
\(\frac{7}{6}*\frac{1}{a}=\frac{1}{b}+\frac{1}{c}\) - combined rate of B and C is 7/6 of rate of A;

\(\frac{10}{3}*\frac{1}{c}=\frac{1}{a}+\frac{1}{b}\) - combined rate of A and B is 10/3 of rate of C;

\(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}=\frac{13}{60}\) - combined rate of A, B and C is 13/60 tank/hour;

Solving:
\(\frac{1}{a}+\frac{7}{6a}=\frac{13}{60}\) --> \(a=10\);

\(\frac{1}{c}+\frac{10}{3c}=\frac{13}{60}\) --> \(c=20\);

\(\frac{1}{10}+\frac{1}{b}+\frac{1}{20}=\frac{13}{60}\) --> \(b=15\).

Answer: B.
Show more

Hi Bunuel,

I have a really stupid question, but I hope you can help me out. Why isn't it 6 (1/A) = 7(1/B + 1/C) leading to a final equation of 6/7 (1/A) = 1/B + 1/C?

Thanks in advanced - as always!!
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,783
Own Kudos:
810,841
 [1]
Given Kudos: 105,853
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,783
Kudos: 810,841
 [1]
A, B, C are three taps connected to a tank such that 6 times 23 Oct 2013, 06:45
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
pauc
Bunuel
cleetus
A, B, C are three taps connected to a tank such that 6 times the time taken by A to fill the tank is 7 times the time taken by B and C together to fill the tank. 3 times the time taken by C to fill the tank is 10 times the time taken by A and B together to fill the tank. If A, B and C together fill the tank in 60/13 hours, then find the time taken by B alone to fill the tank?

A) 10 hrs
B) 15 hrs
C) 20 hrs
D) 25 hrs
E) 30 hrs

Check this: word-translations-rates-work-104208.html?hilit=time%20work#p812628

Let a, b and c be the time needed for A, B and C respectively to fill the tank alone.

Given:
\(\frac{7}{6}*\frac{1}{a}=\frac{1}{b}+\frac{1}{c}\) - combined rate of B and C is 7/6 of rate of A;

\(\frac{10}{3}*\frac{1}{c}=\frac{1}{a}+\frac{1}{b}\) - combined rate of A and B is 10/3 of rate of C;

\(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}=\frac{13}{60}\) - combined rate of A, B and C is 13/60 tank/hour;

Solving:
\(\frac{1}{a}+\frac{7}{6a}=\frac{13}{60}\) --> \(a=10\);

\(\frac{1}{c}+\frac{10}{3c}=\frac{13}{60}\) --> \(c=20\);

\(\frac{1}{10}+\frac{1}{b}+\frac{1}{20}=\frac{13}{60}\) --> \(b=15\).

Answer: B.

Hi Bunuel,

I have a really stupid question, but I hope you can help me out. Why isn't it 6 (1/A) = 7(1/B + 1/C) leading to a final equation of 6/7 (1/A) = 1/B + 1/C?

Thanks in advanced - as always!!
Show more

6 times the time taken by A to fill the tank is 7 times the time taken by B and C together to fill the tank:

Time taken by A is a.
Time taken by B and C together to fill the tank is reciprocal of combined rate of B and C, thus it's bc/(b+c).

Given: \(6a=7*\frac{bc}{b+c}\) --> \(\frac{7}{6}*\frac{1}{a}=\frac{1}{b}+\frac{1}{c}\).

Hope it's clear.
User avatar
ronr34
User avatar
Joined: 08 Apr 2012
Last visit: 10 Oct 2014
Posts: 240
Own Kudos:
253
Given Kudos: 58
Posts: 240
Kudos: 253
A, B, C are three taps connected to a tank such that 6 times 12 Nov 2013, 22:30
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel

6 times the time taken by A to fill the tank is 7 times the time taken by B and C together to fill the tank:

Time taken by A is a.
Time taken by B and C together to fill the tank is reciprocal of combined rate of B and C, thus it's bc/(b+c).

Given: \(6a=7*\frac{bc}{b+c}\) --> \(\frac{7}{6}*\frac{1}{a}=\frac{1}{b}+\frac{1}{c}\).

Hope it's clear.
Show more
Isn't time taken by A supposed to be (1/a)?
And 6 time the time taken by A in 6*(1/a) as per the R*T=W?
I don't get how it's possible to say that a is the time taken by A, and then
when multiplying, you do the multiplication and only then take the reciprocal....
Can you explain this please?
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,783
Own Kudos:
810,841
Given Kudos: 105,853
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,783
Kudos: 810,841
A, B, C are three taps connected to a tank such that 6 times 13 Nov 2013, 01:25
Kudos
Add Kudos
Bookmarks
Bookmark this Post
ronr34
Bunuel

6 times the time taken by A to fill the tank is 7 times the time taken by B and C together to fill the tank:

Time taken by A is a.
Time taken by B and C together to fill the tank is reciprocal of combined rate of B and C, thus it's bc/(b+c).

Given: \(6a=7*\frac{bc}{b+c}\) --> \(\frac{7}{6}*\frac{1}{a}=\frac{1}{b}+\frac{1}{c}\).

Hope it's clear.
Isn't time taken by A supposed to be (1/a)?
And 6 time the time taken by A in 6*(1/a) as per the R*T=W?
I don't get how it's possible to say that a is the time taken by A, and then
when multiplying, you do the multiplication and only then take the reciprocal....
Can you explain this please?
Show more

a is the time taken by A, because I denoted it that way.
User avatar
ronr34
User avatar
Joined: 08 Apr 2012
Last visit: 10 Oct 2014
Posts: 240
Own Kudos:
253
Given Kudos: 58
Posts: 240
Kudos: 253
A, B, C are three taps connected to a tank such that 6 times 13 Nov 2013, 02:01
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
ronr34
Bunuel

6 times the time taken by A to fill the tank is 7 times the time taken by B and C together to fill the tank:

Time taken by A is a.
Time taken by B and C together to fill the tank is reciprocal of combined rate of B and C, thus it's bc/(b+c).

Given: \(6a=7*\frac{bc}{b+c}\) --> \(\frac{7}{6}*\frac{1}{a}=\frac{1}{b}+\frac{1}{c}\).

Hope it's clear.
Isn't time taken by A supposed to be (1/a)?
And 6 time the time taken by A in 6*(1/a) as per the R*T=W?
I don't get how it's possible to say that a is the time taken by A, and then
when multiplying, you do the multiplication and only then take the reciprocal....
Can you explain this please?

a is the time taken by A, because I denoted it that way.
Show more
If so, then why did you take the reciprocal of it for the equations?
Why not leave them with a,b, and c?
I am missing something, but I can't tell what....
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,783
Own Kudos:
810,841
 [1]
Given Kudos: 105,853
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,783
Kudos: 810,841
 [1]
A, B, C are three taps connected to a tank such that 6 times 13 Nov 2013, 02:10
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
ronr34
Bunuel
ronr34

Isn't time taken by A supposed to be (1/a)?
And 6 time the time taken by A in 6*(1/a) as per the R*T=W?
I don't get how it's possible to say that a is the time taken by A, and then
when multiplying, you do the multiplication and only then take the reciprocal....
Can you explain this please?

a is the time taken by A, because I denoted it that way.
If so, then why did you take the reciprocal of it for the equations?
Why not leave them with a,b, and c?
I am missing something, but I can't tell what....
Show more

I think you should go through the basics once more. For example, check here: work-word-problems-made-easy-87357.html or here: two-consultants-can-type-up-a-report-in-12-5-hours-and-edit-126155.html#p1030079

(time)*(rate)=)(job done), thus time to complete one job = reciprocal of rate. For example if 6 hours (time) are needed to complete one job --> 1/6 of the job will be done in 1 hour (rate).
avatar
bazu
avatar
Joined: 17 Aug 2016
Last visit: 06 Apr 2020
Posts: 37
Own Kudos:
15
Given Kudos: 81
Posts: 37
Kudos: 15
A, B, C are three taps connected to a tank such that 6 times 24 Dec 2016, 04:41
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
cleetus
A, B, C are three taps connected to a tank such that 6 times the time taken by A to fill the tank is 7 times the time taken by B and C together to fill the tank. 3 times the time taken by C to fill the tank is 10 times the time taken by A and B together to fill the tank. If A, B and C together fill the tank in 60/13 hours, then find the time taken by B alone to fill the tank?

A) 10 hrs
B) 15 hrs
C) 20 hrs
D) 25 hrs
E) 30 hrs

Check this: word-translations-rates-work-104208.html?hilit=time%20work#p812628

Let a, b and c be the time needed for A, B and C respectively to fill the tank alone.

Given:
\(\frac{7}{6}*\frac{1}{a}=\frac{1}{b}+\frac{1}{c}\) - combined rate of B and C is 7/6 of rate of A;

\(\frac{10}{3}*\frac{1}{c}=\frac{1}{a}+\frac{1}{b}\) - combined rate of A and B is 10/3 of rate of C;

\(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}=\frac{13}{60}\) - combined rate of A, B and C is 13/60 tank/hour;

Solving:
\(\frac{1}{a}+\frac{7}{6a}=\frac{13}{60}\) --> \(a=10\);

\(\frac{1}{c}+\frac{10}{3c}=\frac{13}{60}\) --> \(c=20\);

\(\frac{1}{10}+\frac{1}{b}+\frac{1}{20}=\frac{13}{60}\) --> \(b=15\).

Answer: B.
Show more

Hi Bunuel, how good one should be to finish this problem in 2 min? Because I spent 1:30 to set up all the equations, and even if the solving part is not that complicated it is not even that quick.
User avatar
Kinshook
User avatar
Major Poster
Joined: 03 Jun 2019
Last visit: 23 Apr 2026
Posts: 5,986
Own Kudos:
5,858
 [1]
Given Kudos: 163
Location: India
Schools: HBS '26 CBS '26 Wharton '26
GMAT 1: 690 Q50 V34
WE:Engineering (Transportation)
Products:
My Reviews
Schools: HBS '26 CBS '26 Wharton '26
GMAT 1: 690 Q50 V34
Posts: 5,986
Kudos: 5,858
 [1]
A, B, C are three taps connected to a tank such that 6 times 14 Aug 2022, 23:09
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Given: A, B, C are three taps connected to a tank such that 6 times the time taken by A to fill the tank is 7 times the time taken by B and C together to fill the tank. 3 times the time taken by C to fill the tank is 10 times the time taken by A and B together to fill the tank.

Asked: If A, B and C together fill the tank in 60/13 hours, then find the time taken by B alone to fill the tank?

Let the time taken by taps A, B & C be x, y & z hours respectively

6 times the time taken by A to fill the tank is 7 times the time taken by B and C together to fill the tank.
6x = 7yz/(y+z)
7/x = 6(1/y + 1/z)

3 times the time taken by C to fill the tank is 10 times the time taken by A and B together to fill the tank.
3z = 10xy/(x+y)
10/z = 3(1/x + 1/y)

A, B and C together fill the tank in 60/13 hours
1/x + 1/y + 1/z = 13/60

7/x = 6(1/y + 1/z) = 6(13/60 - 1/x) = 13/10 - 6/x
13/x = 13/10
x = 10 hours

10/z = 3(1/x + 1/y) = 3(13/60 - 1/z) = 13/20 - 3/z
13/z = 13/20
z = 20 hours

1/10 + 1/y + 1/20 = 13/60 = 3/20 + 1/y
1/y = 13/60 - 3/20 = 4/60 = 1/15
y = 15 hours

IMO B
User avatar
Learnerguy
User avatar
Joined: 26 Nov 2024
Last visit: 22 Apr 2026
Posts: 3
Own Kudos:
2
Given Kudos: 46
Posts: 3
Kudos: 2
A, B, C are three taps connected to a tank such that 6 times 14 Mar 2026, 21:20
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Assume Ta, Tb, Tc are time taken by A, B and C to fill the full tank individually.
Given 6*Ta = 7* T(a & b)
3 * Tc = 10 * T(a & b)
Ta + Tb + Tc = 60/13

Ta/ T(a & b) = 7/6 and Tc/ T(a &b) = 10/3

Ta : T(a & b)
7 : 6
As work done is constant, time and efficiency are inversely proportional
Ea : E(b & c)
6 : 7 ----- (1)

Similarly,
Tc : T(a & b)
10 : 3

Ec : E(a & b)
3 : 10 ----- (2)


Adding (1) and (2)
Ea + Ec = 6 + 3 = 9 ---- (3)
Ea + 2Eb + Ec = 17 ---- (4)

(4)-(3)
2Eb = 8
Eb =4

Therefore, Ea=6, Eb=4 and Ec = 3

TW = (Ta + Tb + Tc) * (Ea + Eb + Ec)
= ( 60/13) * ( 6+4+3) [Given total time taken by A,B,C together to fill the tank = 60/13)
= (60/13) * (13)
= 60
TW = 60

Total time taken by B to fill the tank = 60/Eb = 60/4 = 15 hours
Moderators:
Bunuel
Math Expert
109783 posts
Krunaal
Tuck School Moderator
853 posts