Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 05 May 2015, 13:47

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Running at their respective constant rates, machine X takes

Author Message
TAGS:
Director
Joined: 17 Oct 2005
Posts: 940
Followers: 1

Kudos [?]: 63 [0], given: 0

Running at their respective constant rates, machine X takes [#permalink]  06 Feb 2006, 21:56
Running at their respective constant rates, machine X takes 2 days longer to produce w widgets than machine Y. At these rates, if the two machines together produce 5/4 w widgets in 3 days, how many days would it take machine X alone to produce 2w widgets?
VP
Joined: 06 Jun 2004
Posts: 1059
Location: CA
Followers: 2

Kudos [?]: 47 [0], given: 0

x's output per day = 1/(y+2)
y's output per day = 1/y

Working together, they produce (5/4)W in 3 days ==> 5/12W in 1 day

1/(y+2) + 1/y = 5/12 ==> Solve for y, y = 4 or -(6/5). Since y cannot be negative...y = 4

X's output per day is therefore 1/6 ==> it takes x 6 days to produce W ==> 12 days to produce 2W
_________________

Don't be afraid to take a flying leap of faith.. If you risk nothing, than you gain nothing...

Senior Manager
Joined: 05 Jan 2006
Posts: 383
Followers: 1

Kudos [?]: 30 [0], given: 0

12 days! Good one but takes time to resolve

RATExy = Rx + Ry (Rate of x and Rate of y)
RATExy = W/Tx + W/Ty

Now if we assume Tx=n days than Ty will be n-2 days

RATExy = W/n + W/(n-2)

Now we know
Ratexy * 3 days= (5/4)W
3*(W/n + W/(n-2) = 5/4 W
3(1/n + 1(n-2)) = 5/4

solving for this one positive value of n will be 6 so to do 2W work it will take 12 days!
VP
Joined: 21 Sep 2003
Posts: 1066
Location: USA
Followers: 3

Kudos [?]: 39 [0], given: 0

Agree with TeHCM. 12 days.
_________________

"To dream anything that you want to dream, that is the beauty of the human mind. To do anything that you want to do, that is the strength of the human will. To trust yourself, to test your limits, that is the courage to succeed."

- Bernard Edmonds

Similar topics Replies Last post
Similar
Topics:
Running at their respective constant rates, machine X takes 2 03 Nov 2007, 08:32
Running at their respective constant rates, machine X takes 7 22 Sep 2007, 06:52
Running at their respective constant rates, machine X takes 5 30 Aug 2007, 19:37
Running at their respective constant rates, machine X takes 2 11 Mar 2007, 17:07
Running at their respective constant rates, machine X takes 6 07 Dec 2005, 14:43
Display posts from previous: Sort by