Find all School-related info fast with the new School-Specific MBA Forum
Learn more about the recent changes... close

It is currently 23 May 2013, 08:44
Customize  |  Hide

Search
Register
New posts
Unanswered

A boy multiplied 423 by a certain number and obtained 65589

  Question banks Downloads My Bookmarks Reviews  
  Oldest Best Reply
Search for:
 
Print view
First unread post
Author Message
TAGS:
Manager
Manager
Joined: 24 Jan 2005
Posts: 220
Location: Boston
Followers: 1

Kudos [?]: 3 [0], given: 0

GMAT Tests User
A boy multiplied 423 by a certain number and obtained 65589 [#permalink] New post 18 Mar 2005, 15:09
A boy multiplied 423 by a certain number and obtained 65589 as his answer. If both the 5s in the answer are wrong, but the other figures are right, find the correct answer.

(a) 62389
(b) 67889
(c) 60489
(d) 61389

Anirban
Senior Manager
Senior Manager
Joined: 15 Mar 2005
Posts: 432
Location: Phoenix
Followers: 1

Kudos [?]: 7 [0], given: 0

GMAT Tests User
Re: Find the right digits [#permalink] New post 18 Mar 2005, 15:33
anirban16 wrote:
A boy multiplied 423 by a certain number and obtained 65589 as his answer. If both the 5s in the answer are wrong, but the other figures are right, find the correct answer.

(a) 62389
(b) 67889
(c) 60489
(d) 61389

Anirban


(c) 60489.

Apparent observation of the results tell me that the multiplier should end with a three, and should be between 140 and 160.
The possible multiplicants therefore are 143, 153 and 163.
Trying to multiply (don't need to go all the way ... just check upto 2 digits - 153 and 163 don't give 89 as the last 2 digits). Multiply 423 with 143 to arrive at the answer.

Hope that helps.
_________________

Who says elephants can't dance?

SVP
SVP
Joined: 18 Nov 2004
Posts: 1544
Followers: 2

Kudos [?]: 9 [0], given: 0

GMAT Tests User
 [#permalink] New post 18 Mar 2005, 17:01
"C"....anyone knows a quicker way ?....I started with 3 as last digit for the multiplier and work backwards
SVP
SVP
User avatar
Joined: 25 Nov 2004
Posts: 1581
Followers: 4

Kudos [?]: 13 [0], given: 0

GMAT Tests User
Re: Find the right digits [#permalink] New post 18 Mar 2005, 23:04
this is my approach.
lets get the sum of the divider= 4+2+3=9, which means 423 is divided by 3. so does the required number.
lets repeate the process.
(a) the sum is not multiple of 3.
(b) same.
(c) sum = 27
(d) sum = 27

lets do trial and error between C and D. so the answer is 60489.
Manager
Manager
Joined: 24 Jan 2005
Posts: 220
Location: Boston
Followers: 1

Kudos [?]: 3 [0], given: 0

GMAT Tests User
 [#permalink] New post 21 Mar 2005, 19:47
OA is C.
Unfortunatley there is no short cut. You may approximate.
Senior Manager
Senior Manager
User avatar
Joined: 15 Feb 2005
Posts: 258
Location: Rockville
Followers: 1

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

GMAT Tests User
 [#permalink] New post 22 Mar 2005, 09:32
yea i dont think there is any shorter way of doing this
C here too
  [#permalink] 22 Mar 2005, 09:32
    Similar topics Author Replies Last post
Similar
Topics:
 New posts If 4 whole numbers taken at random are multiplied together, Mayur 4 04 Jun 2004, 21:08
New posts A certain set of numbers is formed by multiplying the first GMATT73 4 24 Sep 2005, 17:44
New posts 1 Number S is obtained by squaring the sum of digits of a two feruz77 2 10 Nov 2010, 02:28
New posts multiply numbers GMATD11 3 08 Mar 2011, 08:34
New posts EXPERTS_POSTS_IN_THIS_TOPIC A number a is squared and then multiplied by negative 3. The macjas 2 27 May 2012, 09:22
Display posts from previous: Sort by

A boy multiplied 423 by a certain number and obtained 65589

  Question banks Downloads My Bookmarks Reviews  
Print view
First unread post

Moderators: Bunuel, VeritasPrepKarishma

Search for:


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®.

Main navigation

GMAT Resources

Partners

MBA Resources

www.gmac.com|www.mba.com