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

It is currently 15 Oct 2019, 04:21

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.

Close

Request Expert Reply

Confirm Cancel

Two hoses, Hose X and Hose Y, are used to fill a pool. Working alone,

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

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58327
Two hoses, Hose X and Hose Y, are used to fill a pool. Working alone,  [#permalink]

Show Tags

New post 21 Dec 2017, 20:46
2
14
00:00
A
B
C
D
E

Difficulty:

  55% (hard)

Question Stats:

69% (02:30) correct 31% (02:45) wrong based on 129 sessions

HideShow timer Statistics

Two hoses, Hose X and Hose Y, are used to fill a pool. Working alone, Hose X can fill 1/x of the pool in 15 minutes. What fraction of the pool can Hose Y fill in 15 minutes if, working together, the two hoses can fill the entire pool in one hour?

A. (x−4)/x

B. (x−4)/(4x)

C. (4−x)/x

D. x/(4−x)

E. 4x/(x−4)

_________________
Most Helpful Expert Reply
Senior SC Moderator
avatar
V
Joined: 22 May 2016
Posts: 3538
Two hoses, Hose X and Hose Y, are used to fill a pool. Working alone,  [#permalink]

Show Tags

New post 22 Dec 2017, 18:35
1
4
Bunuel wrote:
Two hoses, Hose X and Hose Y, are used to fill a pool. Working alone, Hose X can fill 1/x of the pool in 15 minutes. What fraction of the pool can Hose Y fill in 15 minutes if, working together, the two hoses can fill the entire pool in one hour?

A. (x−4)/x

B. (x−4)/(4x)

C. (4−x)/x

D. x/(4−x)

E. 4x/(x−4)

This question has a hitch: different units for work rates (minutes vs. hours)

Rate of X

In 15 minutes, Hose X can fill \(\frac{1}{x}\) of the pool
15 minutes = \(\frac{1}{4}\) hour
So in one hour, Hose X can do 4 times as much work as it can in 15 minutes

\((\frac{1}{x} * 4) = \frac{4}{x}\) = hourly work rate of Hose X

Rate of Y

X and Y can fill one pool in one hour
X's rate + Y's rate = \(\frac{1 pool}{1 hr}\) = \(1\)
\(\frac{4}{x}\) + Y's rate = \(1\)
\((1 - \frac{4}{x})\) = Y's rate

\((1 - \frac{4}{x}) = (\frac{x - 4}{x})\) = hourly work rate of Hose Y

Y fills how much?

At that rate, what fraction of the pool can Y fill in 15 minutes (= \(\frac{1}{4}\) hour)?

(Y's work rate per hour, r) * (\(\frac{1}{4}\) hour t) = (work finished W)

\((\frac{x - 4}{x}) * (\frac{1}{4}) = \frac{(x - 4)}{(4x)}\)

Answer B
_________________
SC Butler has resumed! Get two SC questions to practice, whose links you can find by date, here.




Choose life.
General Discussion
VP
VP
User avatar
D
Status: Learning
Joined: 20 Dec 2015
Posts: 1003
Location: India
Concentration: Operations, Marketing
GMAT 1: 670 Q48 V36
GRE 1: Q157 V157
GPA: 3.4
WE: Engineering (Manufacturing)
Reviews Badge
Re: Two hoses, Hose X and Hose Y, are used to fill a pool. Working alone,  [#permalink]

Show Tags

New post 21 Dec 2017, 22:43
1
1
Bunuel wrote:
Two hoses, Hose X and Hose Y, are used to fill a pool. Working alone, Hose X can fill 1/x of the pool in 15 minutes. What fraction of the pool can Hose Y fill in 15 minutes if, working together, the two hoses can fill the entire pool in one hour?

A. (x−4)/x

B. (x−4)/(4x)

C. (4−x)/x

D. x/(4−x)

E. 4x/(x−4)


The answer is E

Hose X can fill 1/x in 15 minutes , then it will fill the tank in 15x minutes
Similarly let us suppose that the fill rate of hose Y is y in 15 minutes then to fill full tank it will take 15y
Setting up the equation we have =1/15x+1/15y=1/60
solving we get 4x/(x-4)
_________________
Please give kudos if you find my answers useful
Intern
Intern
avatar
B
Joined: 09 Apr 2017
Posts: 3
Re: Two hoses, Hose X and Hose Y, are used to fill a pool. Working alone,  [#permalink]

Show Tags

New post 22 Dec 2017, 03:17
1
in 1 hour horse X can fill up: 4/x pool
assuming in 1 hour, horse Y can fill up: 1/y pool
working together horse X and horse Y fill up the tank: 4/x + 1/y = 1
=> 1/y = 1-4/x
in 15 minutes, horse Y will fill up:
1/4y = 1/4*(1-4/x) = (x-4)/4x
So B may be?
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 13154
Re: Two hoses, Hose X and Hose Y, are used to fill a pool. Working alone,  [#permalink]

Show Tags

New post 26 Dec 2018, 12:21
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.
_________________
GMAT Club Bot
Re: Two hoses, Hose X and Hose Y, are used to fill a pool. Working alone,   [#permalink] 26 Dec 2018, 12:21
Display posts from previous: Sort by

Two hoses, Hose X and Hose Y, are used to fill a pool. Working alone,

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





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