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

 It is currently 15 Dec 2019, 14:20

### 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

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

# A rectangular reservoir is filled with water till one-fifth

Author Message
TAGS:

### Hide Tags

Intern
Joined: 10 Dec 2016
Posts: 21
A rectangular reservoir is filled with water till one-fifth  [#permalink]

### Show Tags

14 Mar 2018, 07:52
2
00:00

Difficulty:

65% (hard)

Question Stats:

59% (02:17) correct 41% (03:08) wrong based on 30 sessions

### HideShow timer Statistics

A rectangular reservoir is filled with water till one-fifth of the height of the reservoir. If an outlet at the bottom of the reservoir is unplugged, the water in the reservoir will drain completely in 1 hour. If the outlet remains plugged and the inlet tap at the head of the reservoir is opened, the reservoir will fill to the brim in 2 hours. In how much time will the reservoir fill to the brim if the outlet is unplugged 30 minutes after the inlet tap is opened ?

A) 3 hours

B) 3 hours 30 minutes

C) 4 hours 30 minutes

D) 5 hours

E) The reservoir will never be filled to the brim

Can someone please explain the solution and approach ?
Math Expert
Joined: 02 Aug 2009
Posts: 8326
A rectangular reservoir is filled with water till one-fifth  [#permalink]

### Show Tags

14 Mar 2018, 09:46
1
1
sekharm2389 wrote:
A rectangular reservoir is filled with water till one-fifth of the height of the reservoir. If an outlet at the bottom of the reservoir is unplugged, the water in the reservoir will drain completely in 1 hour. If the outlet remains plugged and the inlet tap at the head of the reservoir is opened, the reservoir will fill to the brim in 2 hours. In how much time will the reservoir fill to the brim if the outlet is unplugged 30 minutes after the inlet tap is opened ?

A) 3 hours

B) 3 hours 30 minutes

C) 4 hours 30 minutes

D) 5 hours

E) The reservoir will never be filled to the brim

Can someone please explain the solution and approach ?

Hi...

1/5 th is filled..
(1) 1 HR to empty it so per HR rate =1/5
(2) 2 HR to fill it completely so (1-1/5=4/5) in 2 hrs..
Full in 2*5/4=5/2, therefore 1 HR wk =2/5..
Combined work = 2/5-1/5=1/5..

Now the reservoir is filled till 1/5. After inlet is on for 1/2 hr, another1/5 is filled since rate is 2/5 in one hour.

So 2/5 is filled when outlet is also opened.
Combined is 1/5, so to do (1-2/5=3/5) work , 3 hrs will be taken..

Total time 30 mins + 3 hrs

B
_________________
A rectangular reservoir is filled with water till one-fifth   [#permalink] 14 Mar 2018, 09:46
Display posts from previous: Sort by