It takes machine A x hours to manufacture a deck of cards : Quant Question Archive [LOCKED]
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 17 Jan 2017, 18:38

### 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

# It takes machine A x hours to manufacture a deck of cards

Author Message
Manager
Joined: 07 Feb 2007
Posts: 54
Followers: 1

Kudos [?]: 5 [0], given: 0

It takes machine A x hours to manufacture a deck of cards [#permalink]

### Show Tags

26 Aug 2007, 19:30
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

It takes machine A x hours to manufacture a deck of cards that machine B can manufacture in 1/x hours. If machine A operates alone for y hours and is then joined by machine B until 100 decks are finished, for how long will the two machines operate simultaneously?

(100y – x)/(x^2 + 1)

(100x – y)/(x^2 + 1)

(100y – x^3 – x)(x^2 + 1)

(100y – x^2y – y)(x^2 + 1)

100x/(x^2 + 1)

Nice question that I came across. Thought of posting it here. Will post OA later.
Manager
Joined: 03 Sep 2006
Posts: 233
Followers: 1

Kudos [?]: 19 [0], given: 0

### Show Tags

27 Aug 2007, 01:00
(1/x)*y + (1/x + x)*Z = 100

[(1 + x^2)/x]*Z = 100 - y/x = (100*x - y)/x

Z = [(100*x - y)/x] / [(1 + x^2)]/x

Z = (100*x - y) / 1 + x^2

P.S> The only thing that we need to understand here is that we should deal with how much work is done by each machine in 1 hour.
CEO
Joined: 29 Mar 2007
Posts: 2583
Followers: 19

Kudos [?]: 420 [0], given: 0

### Show Tags

27 Aug 2007, 15:19
abhi_ferrari wrote:
It takes machine A x hours to manufacture a deck of cards that machine B can manufacture in 1/x hours. If machine A operates alone for y hours and is then joined by machine B until 100 decks are finished, for how long will the two machines operate simultaneously?

(100y – x)/(x^2 + 1)

(100x – y)/(x^2 + 1)

(100y – x^3 – x)(x^2 + 1)

(100y – x^2y – y)(x^2 + 1)

100x/(x^2 + 1)

Nice question that I came across. Thought of posting it here. Will post OA later.

I did VICs prolly not the quickest way since it took me bout 4min
A B ---> rates will equal A: 1/x B: x
R 1/x x
T x 1/x
D 1 1

For me I couldnt figure out how to do this w/ the variables so...

x=2
y=10hrs

A works for 10 hrs at rate of 1/2 (1 deck every 2hrs) so A makes 5 decks.

now B comes in and there is 95 decks remaining. Find the combined rate

1/x+x/1 or 1/2+2=5/2decks/2hrs. (total rate)

use T=D/R 95/5/2= 38hrs

Ok now is where it begins to take a long time... plug in x and y into the answer choices.

E doesnt work, D is ugly and will take awhile to compute w/ the numbers I chose (come back to this if you exhausted the rest of the answers), C doesnt work,

B works....

A doesnt work. I went w/ B since I was just bought to cross 4min
Re: Work Rate problem   [#permalink] 27 Aug 2007, 15:19
Display posts from previous: Sort by