|
Author |
Message |
|
TAGS:
|
|
|
Intern
Joined: 06 Jan 2006
Posts: 23
Location: New York
Followers: 0
Kudos [?]:
0
[0], given: 0
|
Pumps A, B and C operate at their respective constant rates. [#permalink]
 16 Feb 2006, 11:59
Question Stats:
80% (01:28) correct
20% (06:07) wrong based on 4 sessions
Pumps A, B and C operate at their respective constant rates. Pumps A and B operating simultaneously, can fill a certain tank in 6/5 hours; pumps A and C, operating simultaneously can fill the tank in 3/2 hours; and pumps B and C, operating simultaneously can fill the tank in 2 hours. How many hours does it take pumps A, B, and C operating simultaneously to fill the tank.
A- 1/3
B- 1/2
C- 2/3
D- 5/6
E- 1
|
|
|
|
|
|
|
Manager
Joined: 13 Dec 2005
Posts: 226
Location: Milwaukee,WI
Followers: 1
Kudos [?]:
6
[0], given: 0
|
1/a + 1/b = 5/6
1/b +1/c = 2/3
1/c + 1/a =1/2
add all of them together u get
1/a +1/b +1/c = 1
hence they can fill the tank in 1 hr
|
|
|
|
|
|
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5134
Location: Singapore
Followers: 9
Kudos [?]:
87
[0], given: 0
|
1/A + 1/B = 5/6 -- (1)
1/A + 1/C = 2/3 -- (2)
1/B + 1/C = 1/2 -- (3)
(1) - (2)
1/B - 1/C = 1/6 --(3)
1/B + 1/C = 1/2 --(2)
(3) + (2)
2/B = 2/3
1/B = 1/3
1/3 + 1/C = 1/2
1/C = 1/6
1/A + 1/6 = 2/3
1/A = 1/2
1/A + 1/B + 1/C = 1
A + B + C = 1 hour
Ans E
|
|
|
|
|
|
Director
Status: GMAT Learner
Joined: 14 Jul 2010
Posts: 672
Followers: 21
Kudos [?]:
108
[0], given: 31
|
Re: Pumps A, B and C operate at their respective constant rates. [#permalink]
09 Dec 2011, 04:12
Rate of A + B = 5/6---------(i) Rate of A + C = 2/3 --------(ii) Rate of B + C = 1/2 --------(iii) Adding (i), (ii) and (iii) Together 2(A + B +C) = 12/6 = 1 A, B and C took 1 hour. Ans. E
_________________
I am student of everyone-baten
Collections:-
PSof OG solved by GC members: http://gmatclub.com/forum/collection-ps-with-solution-from-gmatclub-110005.html
DS of OG solved by GC members: http://gmatclub.com/forum/collection-ds-with-solution-from-gmatclub-110004.html
100 GMAT PREP Quantitative collection http://gmatclub.com/forum/gmat-prep-problem-collections-114358.html
Collections of work/rate problems with solutions http://gmatclub.com/forum/collections-of-work-rate-problem-with-solutions-118919.html
Mixture problems in a file with best solutions: http://gmatclub.com/forum/mixture-problems-with-best-and-easy-solutions-all-together-124644.html
|
|
|
|
|
|
Manager
Joined: 14 Dec 2011
Posts: 69
GMAT 1: 630 Q48 V29
GMAT 2: 690 Q48 V37
Followers: 1
Kudos [?]:
3
[0], given: 24
|
Re: Pumps A, B and C operate at their respective constant rates. [#permalink]
13 Mar 2012, 02:50
Could someone explain why we use the reciprocal here?
Thanks, alot!
|
|
|
|
|
|
GMAT Club team member
Joined: 02 Sep 2009
Posts: 11633
Followers: 1802
Kudos [?]:
9611
[0], given: 829
|
Re: Pumps A, B and C operate at their respective constant rates. [#permalink]
13 Mar 2012, 03:00
|
|
|
|
|
|
|
Re: Pumps A, B and C operate at their respective constant rates.
[#permalink]
13 Mar 2012, 03:00
|
|
|
|
|
|
|
|
|
Similar topics |
Author |
Replies |
Last post |
|
Similar
Topics:
|
 |
|
|
Pumps A, B and C operate at their respective rates. Pumps A
|
ellisje22 |
1 |
18 Dec 2005, 21:46 |
|
|
|
|
Pumps A,B, and C operate at constant rates. Pumps A & B,
|
zamzim |
4 |
12 Nov 2006, 08:28 |
|
|
|
|
Pumps A, B, and C operate at their respective constant
|
jet1445 |
3 |
20 Feb 2007, 10:31 |
 |
1
|
|
Pumps A, B, and C operate at their respective constant
|
jimmyjamesdonkey |
10 |
21 May 2008, 06:31 |
|
|
14
|
 |
Pumps A, B, and C operate at their respective constant rates
|
chicagocubsrule |
15 |
10 Nov 2009, 15:14 |
|
|
|
|
|
|
close
