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

 It is currently 22 Aug 2019, 04:57 ### 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. ### Request Expert Reply # Water is leaking out from a cylinder container at the rate

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Manager  Joined: 04 Sep 2006
Posts: 109
Water is leaking out from a cylinder container at the rate  [#permalink]

### Show Tags

15 00:00

Difficulty:   45% (medium)

Question Stats: 68% (02:13) correct 32% (02:15) wrong based on 301 sessions

### HideShow timer Statistics

Water is leaking out from a cylinder container at the rate of 0.31 m^3 per minute. 10 minutes later, the water level decreases 0.25 meter, what is value of the radius?

(A) 0.5
(B) 1.0
(C) 1.5
(D) 2.0
(E) 2.5
##### Most Helpful Expert Reply
Math Expert V
Joined: 02 Sep 2009
Posts: 57238
Re: water level  [#permalink]

### Show Tags

4
3
Bullet wrote:
irajeevsingh wrote:
Total water loss = 3.1 mtr in 10 min @.31 meter per min
3.14XR^2X.25 = 3.1
r^2 = 4
r=2

(D)

Can you please elaborate that how you did

3.1 * r^2 * .25 = 3.1

In 10 min the volume of the water which leaked out the cylinder would be $$10*0.31=3.1$$ m^3.

Volume = $$\pi*r^2*height=3.1$$ --> $$\pi*r^2*0.25=3.1$$ --> $$\pi=3.14$$ --> $$3.14*r^2*0.25=3.1$$ --> $$r=2$$ (approximately).

Hope it's clear.
_________________
##### General Discussion
Manager  Joined: 27 Jun 2008
Posts: 126
Re: water level  [#permalink]

### Show Tags

Total water loss = 3.1 mtr in 10 min @.31 meter per min
3.14XR^2X.25 = 3.1
r^2 = 4
r=2

(D)
Intern  Joined: 17 Nov 2009
Posts: 30
Schools: University of Toronto, Mcgill, Queens
Re: water level  [#permalink]

### Show Tags

irajeevsingh wrote:
Total water loss = 3.1 mtr in 10 min @.31 meter per min
3.14XR^2X.25 = 3.1
r^2 = 4
r=2

(D)

Can you please elaborate that how you did

3.1 * r^2 * .25 = 3.1
_________________
--Action is the foundational key to all success.
Intern  Joined: 17 Nov 2009
Posts: 30
Schools: University of Toronto, Mcgill, Queens
Re: water level  [#permalink]

### Show Tags

Bunuel wrote:
Bullet wrote:
irajeevsingh wrote:
Total water loss = 3.1 mtr in 10 min @.31 meter per min
3.14XR^2X.25 = 3.1
r^2 = 4
r=2

(D)

Can you please elaborate that how you did

3.1 * r^2 * .25 = 3.1

In 10 min the volume of the water which leaked out the cylinder would be $$10*0.31=3.1$$ m^3.

Volume = $$\pi*r^2*height=3.1$$ --> $$\pi*r^2*0.25=3.1$$ --> $$\pi=3.14$$ --> $$3.14*r^2*0.25=3.1$$ --> $$r=2$$ (approximately).

Hope it's clear.

Thanks Bunuel, I was confusing 3.14 with the volume where is was pi.

Cheers!
_________________
--Action is the foundational key to all success.
Senior Manager  G
Joined: 27 Aug 2014
Posts: 304
Location: Netherlands
Concentration: Finance, Strategy
Schools: LBS '22, ISB '21
GPA: 3.9
WE: Analyst (Energy and Utilities)
Re: Water is leaking out from a cylinder container at the rate  [#permalink]

### Show Tags

Bunuel wrote:
Bullet wrote:
irajeevsingh wrote:
Total water loss = 3.1 mtr in 10 min @.31 meter per min
3.14XR^2X.25 = 3.1
r^2 = 4
r=2

(D)

Can you please elaborate that how you did

3.1 * r^2 * .25 = 3.1

In 10 min the volume of the water which leaked out the cylinder would be $$10*0.31=3.1$$ m^3.

Volume = $$\pi*r^2*height=3.1$$ --> $$\pi*r^2*0.25=3.1$$ --> $$\pi=3.14$$ --> $$3.14*r^2*0.25=3.1$$ --> $$r=2$$ (approximately).

Hope it's clear.

I have a question, that here it is assumed that the cylinder is standing on the radius and the water is being decreased in the length of the cylinder. Is this a good assumption?
I think this should be stated in the question, as I was trying the problem with the cylinder lying on the length. Math Expert V
Joined: 02 Aug 2009
Posts: 7754
Re: Water is leaking out from a cylinder container at the rate  [#permalink]

### Show Tags

santorasantu wrote:

I have a question, that here it is assumed that the cylinder is standing on the radius and the water is being decreased in the length of the cylinder. Is this a good assumption?
I think this should be stated in the question, as I was trying the problem with the cylinder lying on the length. hi,
since the question says the water decreased by .25m , it would mean that the height of it .. since if it is lying as you have taken, this .25m does not have same cross section at any place...
Also you have to take a cylinder as on base because that is what is the original shape..
you can take the way you have taken only when it is specified that way..
_________________
Intern  Joined: 27 Nov 2014
Posts: 44
Re: Water is leaking out from a cylinder container at the rate  [#permalink]

### Show Tags

chetan2u

hi,
since the question says the water decreased by .25m , it would mean that the height of it .. since if it is lying as you have taken, this .25m does not have same cross section at any place...
Also you have to take a cylinder as on base because that is what is the original shape..
you can take the way you have taken only when it is specified that way..
_____________________________________________________________________________________________________
Chetan i am not convinced from the ans i.e 3.14*$$r^2$$*h
why we took height = .25m as it is not the actual total height ??
and total volume =3.1 as it leaked for 10 min only given.

please help what am i missing ?

Regards
SG
Math Expert V
Joined: 02 Aug 2009
Posts: 7754
Re: Water is leaking out from a cylinder container at the rate  [#permalink]

### Show Tags

1
smartyguy wrote:
.
_____________________________________________________________________________________________________
Chetan i am not convinced from the ans i.e 3.14*$$r^2$$*h
why we took height = .25m as it is not the actual total height ??
and total volume =3.1 as it leaked for 10 min only given.

please help what am i missing ?

Regards
SG

hi SG,

Water is leaking out from a cylinder container at the rate of 0.31 m^3 per minute. 10 minutes later, the water level decreases 0.25 meter, what is value of the radius?

(A) 0.5
(B) 1.0
(C) 1.5
(D) 2.0
(E) 2.5

in one minute, the volume of water lost is .31$$m^3$$
so in 10 minutes the volume of water lost is 3.1$$m^3$$..(1)

now, we are also said that the height lost is .25m, we are not concerned with the entire height...
what is the volume of water in this .25m...
since it is a cylinder the volume of .25 m= pi*$$r^2$$*h=3.14*$$r^2$$*.25...
3.14*$$r^2$$*.25=3.1...
$$r^2$$=1/.25=4.. so r=2 approx
_________________
Intern  Joined: 27 Nov 2014
Posts: 44
Re: Water is leaking out from a cylinder container at the rate  [#permalink]

### Show Tags

chetan2u

Hmm it doesn't matter what is the exact total height and volume .

because radius will remain same.
Thanks again chetan

Regards
SG
Intern  Joined: 27 Nov 2014
Posts: 44
Re: Water is leaking out from a cylinder container at the rate  [#permalink]

### Show Tags

chetan2u

Hmm it doesn't matter what is the exact total height and volume .

because radius will remain same.
Thanks again chetan

Regards
SG
Target Test Prep Representative D
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 7420
Location: United States (CA)
Re: Water is leaking out from a cylinder container at the rate  [#permalink]

### Show Tags

vcbabu wrote:
Water is leaking out from a cylinder container at the rate of 0.31 m^3 per minute. 10 minutes later, the water level decreases 0.25 meter, what is value of the radius?

(A) 0.5
(B) 1.0
(C) 1.5
(D) 2.0
(E) 2.5

Since the rate of leaking is 0.31 m^3 per minute, in 10 minutes, 10 x 0.31 = 3.1 m^3 of water has been leaked. Let’s let r = radius of the cylinder. Recall that the formula for the volume of a right circular cylinder is V = πr^2h. Using the volume of water leaked and the height associated with that volume, we can create the following equation:

πr^2 x 0.25 = 3.1

πr^2 / 4 = 3.1

r^2 = 3.1 x 4 / π

Notice that π ≈ 3.1, thus we have:

r^2 = 4

r = 2

Answer: D
_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

VP  G
Joined: 09 Mar 2018
Posts: 1001
Location: India
Re: Water is leaking out from a cylinder container at the rate  [#permalink]

### Show Tags

vcbabu wrote:
Water is leaking out from a cylinder container at the rate of 0.31 m^3 per minute. 10 minutes later, the water level decreases 0.25 meter, what is value of the radius?

(A) 0.5
(B) 1.0
(C) 1.5
(D) 2.0
(E) 2.5

Sometimes i tell you,WHY You can get the change in volume as 3.1 $$m^3$$, 0.31 m^3 per minute, in 10 mins just multiply it with 10

Now level decreases by 0.25, this directly means the new height

3.14 * r^2 * 1/4 = 3.1
r^2 = 4

We can cancel 3.14 from both sides now

For starters, this cannot be 1.5,

root4 = 2
root3 = 1.732
root5 = 2.124

Answer is D
_________________
If you notice any discrepancy in my reasoning, please let me know. Lets improve together.

Quote which i can relate to.
Many of life's failures happen with people who do not realize how close they were to success when they gave up.
GMAT Club Legend  D
Joined: 18 Aug 2017
Posts: 4512
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
Re: Water is leaking out from a cylinder container at the rate  [#permalink]

### Show Tags

vcbabu wrote:
Water is leaking out from a cylinder container at the rate of 0.31 m^3 per minute. 10 minutes later, the water level decreases 0.25 meter, what is value of the radius?

(A) 0.5
(B) 1.0
(C) 1.5
(D) 2.0
(E) 2.5

good quesiton
rate of flow 0.31 m^3 per minute
so in 10 mins water flowed out 3.1m^3 and height = .25 mtr
so
pi *r^2*.25=3.1

solve we get r=2
IMO D
_________________
If you liked my solution then please give Kudos. Kudos encourage active discussions. Re: Water is leaking out from a cylinder container at the rate   [#permalink] 02 Jun 2019, 09:46
Display posts from previous: Sort by

# Water is leaking out from a cylinder container at the rate

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

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

#### MBA Resources  