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

It is currently 30 Jun 2015, 21:33

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Four flash lights begin to flash light together and then at

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Senior Manager
Senior Manager
User avatar
Joined: 30 Aug 2003
Posts: 330
Location: BACARDIVILLE
Followers: 1

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

Four flash lights begin to flash light together and then at [#permalink] New post 01 Mar 2004, 13:08
Four flash lights begin to flash light together and then at intervals of 6,7,8 and 9 seconds respectively. How many times will the flash lights be on together in a duration of 2 hrs?

14
18
144
504
604
_________________

Pls include reasoning along with all answer posts.
****GMAT Loco****
Este examen me conduce jodiendo loco

Director
Director
avatar
Joined: 03 Jul 2003
Posts: 654
Followers: 2

Kudos [?]: 32 [0], given: 0

 [#permalink] New post 01 Mar 2004, 13:37
Ans: A


Total sec in 2 hours = 2 * 60 * 60
Lights flash togather at an interval of 504 sec.
Divide and we get 14.
SVP
SVP
User avatar
Joined: 30 Oct 2003
Posts: 1794
Location: NewJersey USA
Followers: 5

Kudos [?]: 43 [0], given: 0

 [#permalink] New post 05 Mar 2004, 13:59
Let me explain it

Let us say one light flashes at 2 seconds and another at 5 seconds then they both coincide at 10 seconds. In 20 seconds they coincide 2 times in 40 seconds they do 4 times.
They way to solve this is take LCm of 2 and 5 you get 10
in 40 seconds they coincide 40/10 = 4 times
LCM of ( 6,7,8,9 ) is 504
In 2 hours we have 60 * 60 * 2 seconds
So they flash together 7200/504 times = 14 times.
  [#permalink] 05 Mar 2004, 13:59
    Similar topics Author Replies Last post
Similar
Topics:
why aren't the flash cards stickied? btan219 0 13 Feb 2015, 08:42
lights ritula 2 13 Feb 2009, 03:33
throw some light on the meaning.. arjtryarjtry 4 12 Sep 2008, 05:28
A teacher uses 10 flash cards numbered 1 through 10. She bmwhype2 1 16 Feb 2008, 22:43
I am preparing flash cards and any insight the following are prasannar 1 17 Jan 2008, 00:34
Display posts from previous: Sort by

Four flash lights begin to flash light together and then at

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

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®.