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

 It is currently 21 Aug 2018, 19:01

### 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 Hydrogenator water gun has a cylindrical water tank, which is 30

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 48110
A Hydrogenator water gun has a cylindrical water tank, which is 30  [#permalink]

### Show Tags

02 Jul 2015, 01:47
00:00

Difficulty:

45% (medium)

Question Stats:

67% (01:14) correct 33% (01:32) wrong based on 158 sessions

### HideShow timer Statistics

A Hydrogenator water gun has a cylindrical water tank, which is 30 centimeters long. Using a hose, Jack fills his Hydrogenator with $$\pi$$ cubic centimeters of his water tank every second. If it takes him 8 minutes to fill the tank with water, what is the diameter of the circular base of the gun's water tank?

A. 1 cm
B. 2 cm
C. 4 cm
D. 8 cm
E. 16 cm

Kudos for a correct solution.

_________________
Manager
Status: Perspiring
Joined: 15 Feb 2012
Posts: 106
Concentration: Marketing, Strategy
GPA: 3.6
WE: Engineering (Computer Software)
Re: A Hydrogenator water gun has a cylindrical water tank, which is 30  [#permalink]

### Show Tags

02 Jul 2015, 02:45
Formula used : Volume of a cylinder = area of base * height = π*r*r*h

Filling rate = π cm cube per sec ----------- (1)
Total time to fill = 8 mins = 480 secs ------------ (2)

From 1 & 2, Total volume filled = π*480 -------------- (3)

Now, we know that
π*r*r*30 = Total volume ----------- (4)

Solving 3 & 4,
r = 4
Hence C !!
Current Student
Joined: 22 Apr 2015
Posts: 48
Location: United States
GMAT 1: 620 Q46 V27
GPA: 3.86
Re: A Hydrogenator water gun has a cylindrical water tank, which is 30  [#permalink]

### Show Tags

02 Jul 2015, 09:31
NickHalden wrote:
Formula used : Volume of a cylinder = area of base * height = π*r*r*h

Filling rate = π cm cube per sec ----------- (1)
Total time to fill = 8 mins = 480 secs ------------ (2)

From 1 & 2, Total volume filled = π*480 -------------- (3)

Now, we know that
π*r*r*30 = Total volume ----------- (4)

Solving 3 & 4,
r = 4
Hence C !!

I did all that you did but since it asks for the diameter shouldn't it be 8 (4*2)?
Senior Manager
Joined: 28 Feb 2014
Posts: 295
Location: United States
Concentration: Strategy, General Management
Re: A Hydrogenator water gun has a cylindrical water tank, which is 30  [#permalink]

### Show Tags

02 Jul 2015, 10:08
1
Volume as filled by hose=60×8×pi

Volume of cylinder=pi×r^2×30

60×8×pi=pi×r^2×30
r=4 so diameter=8

D. 8 cm
Manager
Joined: 18 Mar 2014
Posts: 231
Location: India
Concentration: Operations, Strategy
GMAT 1: 670 Q48 V35
GPA: 3.19
WE: Information Technology (Computer Software)
Re: A Hydrogenator water gun has a cylindrical water tank, which is 30  [#permalink]

### Show Tags

03 Jul 2015, 09:15
volume = 480 *pi

Pi*r^2*h = 480 pi
r^2 * 30 = 480

so r = 4
And diameter = 8
_________________

Press +1 Kudos if you find this Post helpful

Senior Manager
Joined: 27 Jul 2014
Posts: 300
Schools: ISB '15
GMAT 1: 660 Q49 V30
GPA: 3.76
Re: A Hydrogenator water gun has a cylindrical water tank, which is 30  [#permalink]

### Show Tags

04 Jul 2015, 12:25
D is correct
Volume as filled by hose=60×8×pi

Volume of cylinder=pi×r^2×30

60×8×pi=pi×r^2×30
r=4 so diameter = 8
Current Student
Joined: 20 Mar 2014
Posts: 2643
Concentration: Finance, Strategy
Schools: Kellogg '18 (M)
GMAT 1: 750 Q49 V44
GPA: 3.7
WE: Engineering (Aerospace and Defense)
Re: A Hydrogenator water gun has a cylindrical water tank, which is 30  [#permalink]

### Show Tags

04 Jul 2015, 13:27
Bunuel wrote:
A Hydrogenator water gun has a cylindrical water tank, which is 30 centimeters long. Using a hose, Jack fills his Hydrogenator with $$\pi$$ cubic centimeters of his water tank every second. If it takes him 8 minutes to fill the tank with water, what is the diameter of the circular base of the gun's water tank?

A. 1 cm
B. 2 cm
C. 4 cm
D. 8 cm
E. 16 cm

Kudos for a correct solution.

Height of the cylinder = h = 30 cm

Rate of filling the tank = R = $$\pi \frac{{cm}^3}{s}$$

Time it takes to fill the tank = t=8 minutes = 480 seconds

Thus, volume of the cylinder (with radius of the base of the base of the cylinder = r cm) = V = R*t = $$480\pi$$ = $$\pi*r^2*h$$

Thus r = 4 cm and diameter = 2r =8 cm. D is the correct answer.
Director
Joined: 21 May 2013
Posts: 649
Re: A Hydrogenator water gun has a cylindrical water tank, which is 30  [#permalink]

### Show Tags

05 Jul 2015, 03:33
1
Bunuel wrote:
A Hydrogenator water gun has a cylindrical water tank, which is 30 centimeters long. Using a hose, Jack fills his Hydrogenator with $$\pi$$ cubic centimeters of his water tank every second. If it takes him 8 minutes to fill the tank with water, what is the diameter of the circular base of the gun's water tank?

A. 1 cm
B. 2 cm
C. 4 cm
D. 8 cm
E. 16 cm

Kudos for a correct solution.

Height of cylinder tank=30 cm
Rate of filling = Pie cu cm per second
8 minutes=8*60=480 seconds
Volume of tank =pie r^2*h=pie*r^2*30=480 pie
diamter=8 cm
Math Expert
Joined: 02 Sep 2009
Posts: 48110
Re: A Hydrogenator water gun has a cylindrical water tank, which is 30  [#permalink]

### Show Tags

06 Jul 2015, 07:22
1
Bunuel wrote:
A Hydrogenator water gun has a cylindrical water tank, which is 30 centimeters long. Using a hose, Jack fills his Hydrogenator with $$\pi$$ cubic centimeters of his water tank every second. If it takes him 8 minutes to fill the tank with water, what is the diameter of the circular base of the gun's water tank?

A. 1 cm
B. 2 cm
C. 4 cm
D. 8 cm
E. 16 cm

Kudos for a correct solution.

MANHATTAN GMAT OFFICIAL SOLUTION:

In 8 minutes, or 480 seconds, $$480\pi$$ cm3 of water flows into the tank. Therefore, the volume of the tank is $$480\pi$$. You are given a height of 30, so you can solve for the radius:

$$V = \pi r^2 * h$$

$$480\pi = 30\pi r^2$$

$$r^2 = 16$$

$$r= 4$$

Therefore, the diameter of the tanks base is 8 cm.

_________________
Current Student
Joined: 12 Aug 2015
Posts: 2650
Schools: Boston U '20 (M)
GRE 1: Q169 V154
A hydrogenator water gun has a cylinderical water tank ; which is 30 c  [#permalink]

### Show Tags

01 Apr 2016, 15:10
A hydrogenator water gun has a cylinderical water tank ; which is 30 cm long .Using a hose, jack fills the tank with π cubic cm of water every scond. If it takes 8 minutes to fill the tank completely with water => the diameter of the tank is
[A] 4
[B] 8
[C] 12
[D] 16
[E] 20
_________________

MBA Financing:- INDIAN PUBLIC BANKS vs PRODIGY FINANCE!

Getting into HOLLYWOOD with an MBA!

The MOST AFFORDABLE MBA programs!

STONECOLD's BRUTAL Mock Tests for GMAT-Quant(700+)

AVERAGE GRE Scores At The Top Business Schools!

Math Expert
Joined: 02 Sep 2009
Posts: 48110
Re: A Hydrogenator water gun has a cylindrical water tank, which is 30  [#permalink]

### Show Tags

01 Apr 2016, 15:14
Chiragjordan wrote:
A hydrogenator water gun has a cylinderical water tank ; which is 30 cm long .Using a hose, jack fills the tank with π cubic cm of water every scond. If it takes 8 minutes to fill the tank completely with water => the diameter of the tank is
[A] 4
[B] 8
[C] 12
[D] 16
[E] 20

Merging topics. Please refer to the discussion above.
_________________
Non-Human User
Joined: 09 Sep 2013
Posts: 7780
Re: A Hydrogenator water gun has a cylindrical water tank, which is 30  [#permalink]

### Show Tags

03 Aug 2018, 10:50
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Re: A Hydrogenator water gun has a cylindrical water tank, which is 30 &nbs [#permalink] 03 Aug 2018, 10:50
Display posts from previous: Sort by

# Events & Promotions

 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®.