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

It is currently 21 Feb 2019, 08:40
Register
GMAT Club Tests
Decision Tracker
My Rewards
New comers' posts
New posts
Unanswered

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
Events & Promotions in February
PrevNext
SuMoTuWeThFrSa
272829303112
3456789
10111213141516
17181920212223
242526272812
Open Detailed Calendar

  • Online GMAT boot camp for FREE

     February 21, 2019

     February 21, 2019

     10:00 PM PST

     11:00 PM PST

    Kick off your 2019 GMAT prep with a free 7-day boot camp that includes free online lessons, webinars, and a full GMAT course access. Limited for the first 99 registrants! Feb. 21st until the 27th.
    GMAT: Verbal | GMAT: Quantitative | Free

  • Free GMAT RC Webinar

     February 23, 2019

     February 23, 2019

     07:00 AM PST

     09:00 AM PST

    Learn reading strategies that can help even non-voracious reader to master GMAT RC. Saturday, February 23rd at 7 AM PT
    GMAT: Verbal | GMAT: Quantitative | Free
CLICK HERE TO HIDE/SHOW EVENTS

Two pipes A and B can fill a tank in 8 hours. If only pipe A is open

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
  Sort by Date Sort by Kudos  
Search for:
 
Print view
First unread post
Author Message
TAGS:

Hide Tags

 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 53063
Premium Member
Top Member of the Month
Two pipes A and B can fill a tank in 8 hours. If only pipe A is open  [#permalink]

Show Tags

New post 31 Jan 2019, 08:07
2
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

74% (01:41) correct 26% (01:35) wrong based on 46 sessions

HideShow timer Statistics

Two pipes A and B can fill a tank in 8 hours. If only pipe A is open then it would take 4 hours longer to fill the tank. Find how much longer would it take if only pipe B is open.

A. 6 hours
B. 8 hours
C. 10 hours
D. 12 hours
E. 16 hours
Spoiler: OA

_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

SVP
SVP
User avatar
G
Joined: 18 Aug 2017
Posts: 1905
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
GMAT ToolKit User Premium Member CAT Tests
Two pipes A and B can fill a tank in 8 hours. If only pipe A is open  [#permalink]

Show Tags

New post 31 Jan 2019, 08:12
Bunuel wrote:
Two pipes A and B can fill a tank in 8 hours. If only pipe A is open then it would take 4 hours longer to fill the tank. Find how much longer would it take if only pipe B is open.

A. 6 hours
B. 8 hours
C. 10 hours
D. 12 hours
E. 16 hours


given
AB/A+B = 1/8

time of A = 4 + 8 ; 12 hours
so
12B/12+B= 1/8
solve
B = 24 hours
so B would take 24-8 = 16 hours longer
IMO E
_________________

If you liked my solution then please give Kudos. Kudos encourage active discussions.

Director
Director
User avatar
P
Joined: 04 Sep 2015
Posts: 547
Location: India
WE: Information Technology (Computer Software)
Premium Member Reviews Badge CAT Tests
Re: Two pipes A and B can fill a tank in 8 hours. If only pipe A is open  [#permalink]

Show Tags

New post 31 Jan 2019, 08:52
Bunuel wrote:
Two pipes A and B can fill a tank in 8 hours. If only pipe A is open then it would take 4 hours longer to fill the tank. Find how much longer would it take if only pipe B is open.

A. 6 hours
B. 8 hours
C. 10 hours
D. 12 hours
E. 16 hours



solution:

rate of A+rate of B= total rate, and if the work done is one then we get the total time to finish.

1/A+1/B=1/Total

1/A+1/B=1/8. and given that rate of A=8+4=12 hours

so 1/12+1/B=1/8

1/B=1/8-1/12.. we get B as 24, now, how much longer tha 8 will it take then 24-8=16.

Option E.16 hours more
Target Test Prep Representative
User avatar
P
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 4944
Location: United States (CA)
Re: Two pipes A and B can fill a tank in 8 hours. If only pipe A is open  [#permalink]

Show Tags

New post 04 Feb 2019, 18:02
Bunuel wrote:
Two pipes A and B can fill a tank in 8 hours. If only pipe A is open then it would take 4 hours longer to fill the tank. Find how much longer would it take if only pipe B is open.

A. 6 hours
B. 8 hours
C. 10 hours
D. 12 hours
E. 16 hours


Let’s let B = the number of hours it takes pipe B to fill the tank. We see that the combined rate of A and B is 1/8, and since pipe A can fill the tank in 8 + 4 = 12 hours, the rate of pipe A is 1/12 and the rate of pipe B is 1/B; thus:

1/12 + 1/B = 1/8

Multiplying by 24B, we have:

2B + 24 = 3B

B = 24

So it would take 24 - 8 = 16 hours longer if only B is open.

Answer: E
_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

GMAT Club Bot
Re: Two pipes A and B can fill a tank in 8 hours. If only pipe A is open   [#permalink] 04 Feb 2019, 18:02
Print view
First unread post
Display posts from previous: Sort by

Two pipes A and B can fill a tank in 8 hours. If only pipe A is open

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  

Moderators: chetan2u, Bunuel, VeritasKarishma, Gladiator59, generis

Search for:


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.

Main navigation

GMAT Resources

Partners

MBA Resources

www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions