Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 563 reviewsTarget Test Prep

tank filling # time taken

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 392
Joined: Sun May 16, 2010 2:42 amFollowed by: 10 members
Location: Bangalore, India
Thanked: 116 times
GMAT Score:770

by albatross86 » Tue Jun 29, 2010 4:46 am
Identical taps = same rate

First 20 minutes was at twice the rate
Next T minutes would be at only one rate

=> 2R*20 = 2/5C

=> R = C/100

And for the rest of the tank we have:

=> R*T = 3/5C

Substituting value of R:

=> C/100 * T = 3/5 C

=> T = 60 minutes
~Abhay

Believe those who are seeking the truth. Doubt those who find it. -- Andre Gide
Top
Join the discussion
User avatar
Legendary Member
Posts: 1460
Joined: Tue Dec 29, 2009 1:28 amFollowed by: 7 members
Thanked: 135 times

by selango » Tue Jun 29, 2010 6:14 am
Tap A complete work in X minutes.So in 1 min it complete 1/X unit of work.

similarly Tap B complete 1/X unit of work in 1 min.[Same rate for both taps]

20*(1/x+1/x)=2/5

20*(2/x)=2/5

x=100

Now Tap A fill 3/5 of tank and T be number of minutes

T*(1/100)=3/5

T=60 mins
Top
Join the discussion
Senior | Next Rank: 100 Posts
Posts: 30
Joined: Sun Jun 27, 2010 7:55 pm

by [email protected] » Tue Jun 29, 2010 7:47 am
Two identical taps fill 2/5 of a tank in 20 minutes. When one of the taps goes dry in how many minutes will the
remaining one tap fill the rest of the tank ?
A. 5 minutes
B. 10 minutes
C. 15 minutes
D. 20 minutes
E. None of the above
Top
Join the discussion
User avatar
Legendary Member
Posts: 1460
Joined: Tue Dec 29, 2009 1:28 amFollowed by: 7 members
Thanked: 135 times

by selango » Tue Jun 29, 2010 7:51 am
Its option E
Top
Join the discussion
Master | Next Rank: 500 Posts
Posts: 151
Joined: Thu Apr 22, 2010 4:07 pm
Thanked: 14 times

by Haaress » Tue Jun 29, 2010 7:59 am
Ofcourse one can use the algebraic method to solve this question, but I guess the quickest method is logic in this case.

If 2 taps can fill 2/5 in 20 minutes, then 1 tap fills 1/5 in 20 minutes.

So give the tank is 2/5 full, the remaining part s 3/5. The only running tap takes 20 minutes to fill 1/5, so it will take 20(3) to fill 1/5 (3) .

Thus 60 minutes or E in this case.
Top
Join the discussion
Master | Next Rank: 500 Posts
Posts: 294
Joined: Wed May 05, 2010 4:01 am
Location: india
Thanked: 57 times

by amising6 » Tue Jun 29, 2010 8:05 am
[email protected] wrote:Two identical taps fill 2/5 of a tank in 20 minutes. When one of the taps goes dry in how many minutes will the
remaining one tap fill the rest of the tank ?
A. 5 minutes
B. 10 minutes
C. 15 minutes
D. 20 minutes
E. None of the above
so both the taps filling individually 1/5 in 20 minutes
tank to be filled 4/5
now one of them will fill reamining 4/5 in 20*4=80 mins
Ideation without execution is delusion
Top
Join the discussion
User avatar
Legendary Member
Posts: 1460
Joined: Tue Dec 29, 2009 1:28 amFollowed by: 7 members
Thanked: 135 times

by selango » Tue Jun 29, 2010 8:09 am
amising6 wrote:
[email protected] wrote:Two identical taps fill 2/5 of a tank in 20 minutes. When one of the taps goes dry in how many minutes will the
remaining one tap fill the rest of the tank ?
A. 5 minutes
B. 10 minutes
C. 15 minutes
D. 20 minutes
E. None of the above
so both the taps filling individually 1/5 in 20 minutes
tank to be filled 4/5
now one of them will fill reamining 4/5 in 20*4=80 mins

amising6,

already 2/5 of tank is filled.Remaining 3/5 of tank only need to be filled.

3/5=3*1/5=3*20=60
Top
Join the discussion
Master | Next Rank: 500 Posts
Posts: 294
Joined: Wed May 05, 2010 4:01 am
Location: india
Thanked: 57 times

by amising6 » Tue Jun 29, 2010 8:19 am
selango wrote:
amising6 wrote:
[email protected] wrote:Two identical taps fill 2/5 of a tank in 20 minutes. When one of the taps goes dry in how many minutes will the
remaining one tap fill the rest of the tank ?
A. 5 minutes
B. 10 minutes
C. 15 minutes
D. 20 minutes
E. None of the above
so both the taps filling individually 1/5 in 20 minutes
tank to be filled 4/5
now one of them will fill reamining 4/5 in 20*4=80 mins
ohh yes thanks


amising6,

already 2/5 of tank is filled.Remaining 3/5 of tank only need to be filled.

3/5=3*1/5=3*20=60
Ideation without execution is delusion
Top
Join the discussion