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

 It is currently 19 May 2013, 17:02

# lets do some real problems...shall we?...math section of

 Question banks Downloads My Bookmarks Reviews
Author Message
TAGS:
Current Student
Joined: 28 Dec 2004
Posts: 3439
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 11

Kudos [?]: 134 [0], given: 2

lets do some real problems...shall we?...math section of [#permalink]  09 Sep 2005, 07:32
lets do some real problems...shall we?...math section of late has become relatively dormant...

The workforce of a certain company comprised exactly 10,500 employees after a four-year period during which it increased every year. During this four-year period, the ratio of the number of workers from one year to the next was always an integer. The ratio of the number of workers after the fourth year to the number of workers after the the second year is 6 to 1. The ratio of the number of workers after the third year to the number of workers after the first year is 14 to 1. The ratio of the number of workers after the third year to the number of workers before the four-year period began is 70 to 1. How many employees did the company have after the first year?

(A) 50
(B) 70
(C) 250
(D) 350
(E) 750
Senior Manager
Joined: 27 Aug 2005
Posts: 333
Location: Montreal, Canada
Followers: 2

Kudos [?]: 1 [0], given: 0

[#permalink]  09 Sep 2005, 08:43
10,500/6 = 1,750 = number of workers after the second year

Now we need a number of workers after the third year. Let it = X. We have some clues to get to X:
- 10,500/X is an integer greater than 1.
-X/1,750 is an integer greater than 1.

We note that 10,500/1750 = 6. So we need two integer factors of 6, and neither factor can be 1. This means that the factors are 2 and 3.

Therefore we have two possibilities: either X is 3,500 or X is 5,250.

But we know that the ratio of the number of workers after the third year to the number of workers after the first year is 14 to 1.

3,500/14 = 250
5,250/14 = 375

So the number of workers after the first year is either 250 or 375. But this has to be an integer ratio with the number of workers after the second year, which is 1,750. Of the two possibilities, only 250 satisfies the condition, because 1,750/250 = 7 and 1,750/375 = 4 2/3.

Therefore the number of workers after the first year is 250. Answer C.
Senior Manager
Joined: 29 Nov 2004
Posts: 491
Location: Chicago
Followers: 1

Kudos [?]: 2 [0], given: 0

[#permalink]  09 Sep 2005, 10:21
A and B are too low it gives less employess in 3rd year than second year so chuck it

250 gives

50 - 250 - 1750 - 3500 - 10500
(all ratios in integer)

D, E does not give integer ratios...so C
_________________

Fear Mediocrity, Respect Ignorance

Intern
Joined: 20 Jul 2005
Posts: 21
Followers: 0

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

[#permalink]  09 Sep 2005, 10:35
My answer is also c.

x --> x1--> x2 --> x3 --> x4

x4 is 10,500 & x4:x2=6:1 i.e. x2=1750
x3:x1=14:1
x3:x=70:1

I started with choice c. x1=250

50--> 250 --> 1750 --> 3500 --> 10,500

Chocie A returns x3=700 which is less than x2=1750, so it has to be ruled out and Choice B can also be ruled out.

No other answer choice returns an integer ratio.
Current Student
Joined: 28 Dec 2004
Posts: 3439
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 11

Kudos [?]: 134 [0], given: 2

[#permalink]  09 Sep 2005, 11:21
Good...but hint is you should know your number properties and prime factors./...will post OA later today...
[#permalink] 09 Sep 2005, 11:21
Similar topics Replies Last post
Similar
Topics:
7 Let's do this one 5 31 Aug 2009, 04:29
2 710 and letting go: what to do, and what not to do 18 24 Jun 2010, 05:36
Let's have some fun with English! 7 07 Sep 2010, 08:34
come om lets do it together!!!! 3 16 Jun 2011, 20:16
Real GMAT Integrated Reasoning Section 3 26 Jan 2013, 13:16
Display posts from previous: Sort by

# lets do some real problems...shall we?...math section of

 Question banks Downloads My Bookmarks Reviews

 Powered by phpBB © phpBB Group and phpBB SEO 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®.