Last visit was: 03 May 2026, 20:44 It is currently 03 May 2026, 20:44
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
User avatar
sonibubu
User avatar
Current Student
Joined: 20 Aug 2007
Last visit: 18 Aug 2011
Posts: 810
Own Kudos:
158
Given Kudos: 1
Location: Chicago
Concentration: Strategy, Management, Finance
Schools:Chicago Booth 2011
Posts: 810
Kudos: 158
A pond has an inlet to fill it up and an outlet to drain it. 27 Feb 2008, 19:15
Kudos
Add Kudos
Bookmarks
Bookmark this Post
A pond has an inlet to fill it up and an outlet to drain it. The inlet can fill it in 5 hours and the the outlet can drain it in 8 hours. Suppose the pond was empty and the person in charge of filling it up opened the inlet but forgot to close the outlet. After 4 hours, he realized that the outlet is still open. At that time, he closed the outlet. How long did it take for the pond to get filled after the outlet was closed?

a) 5
b) 4
c) 3.5
d) 7
e) 8



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
avatar
x1050us
avatar
Joined: 25 Feb 2008
Last visit: 20 Mar 2008
Posts: 3
Own Kudos:
5
 [1]
Posts: 3
Kudos: 5
 [1]
A pond has an inlet to fill it up and an outlet to drain it. 27 Feb 2008, 20:30
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
sonibubu
A pond has an inlet to fill it up and an outlet to drain it. The inlet can fill it in 5 hours and the the outlet can drain it in 8 hours. Suppose the pond was empty and the person in charge of filling it up opened the inlet but forgot to close the outlet. After 4 hours, he realized that the outlet is still open. At that time, he closed the outlet. How long did it take for the pond to get filled after the outlet was closed?

a) 5
b) 4
c) 3.5
d) 7
e) 8
Show more

after 4hrs = 80% - 50% = 30% filled
100% takes = 5 hr remaining => 70% takes 3.5 hours
User avatar
GMATBLACKBELT
User avatar
Joined: 29 Mar 2007
Last visit: 03 Jun 2013
Posts: 1,138
Own Kudos:
1,915
Posts: 1,138
Kudos: 1,915
A pond has an inlet to fill it up and an outlet to drain it. 28 Feb 2008, 07:13
Kudos
Add Kudos
Bookmarks
Bookmark this Post
sonibubu
A pond has an inlet to fill it up and an outlet to drain it. The inlet can fill it in 5 hours and the the outlet can drain it in 8 hours. Suppose the pond was empty and the person in charge of filling it up opened the inlet but forgot to close the outlet. After 4 hours, he realized that the outlet is still open. At that time, he closed the outlet. How long did it take for the pond to get filled after the outlet was closed?

a) 5
b) 4
c) 3.5
d) 7
e) 8
Show more

C? this question was kinda confusing cause I thought it was asking for the total time.

Anyway. 4*1/5 = 4/5 4*1/8 ---> 1/2 --> 4/5-1/2=3/10

so we have 7/10 remaining.

Now its just 7/10/1/5 --> 35/10 = 3.5



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!