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

It is currently 24 Jul 2014, 19:44

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

The sum of Doris and Fred's ages is y . Doris is 12 years

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Intern
Intern
avatar
Joined: 16 Sep 2006
Posts: 22
Followers: 0

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

The sum of Doris and Fred's ages is y . Doris is 12 years [#permalink] New post 16 Sep 2006, 19:02
The sum of Doris and Fred's ages is y. Doris is 12 years older than Fred. How many years old will Fred be y years from now, in terms of y.
A. y-6
b. 2y-6
C. y/2-6
D. 3y/2-6
E. 5y/2-6

I have the answer by plugging in numbers, but can't figure out how this formula came about. Any help would be greatly appreciated. Thanks.
Manager
Manager
User avatar
Joined: 23 Jul 2006
Posts: 50
Followers: 1

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

 [#permalink] New post 16 Sep 2006, 19:19
Hi.

You have:

D + F = Y

and you have that:

D = F + 12

If you replace the second equation in the first euation, we have:

2F + 12 = Y => F = (Y-12)/2

That is the Fred´s age today. In y more years will be: F + Y ==>

==> (Y-12)/2 + Y ==> (3/2)Y - 6 ..... (D)
_________________

Woody crack the GMAT

Intern
Intern
avatar
Joined: 16 Sep 2006
Posts: 22
Followers: 0

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

 [#permalink] New post 16 Sep 2006, 19:29
Thank you, I can sleep now...
SVP
SVP
User avatar
Joined: 05 Jul 2006
Posts: 1542
Followers: 5

Kudos [?]: 65 [0], given: 39

 [#permalink] New post 17 Sep 2006, 01:56
The sum of Doris and Fred's ages is y. Doris is 12 years older than Fred. How many years old will Fred be y years from now, in terms of y.
A. y-6
b. 2y-6
C. y/2-6
D. 3y/2-6
E. 5y/2-6

D+F = Y BUT F+12 = D THUS 2F +12 = Y

F NOW = Y-12/2 , F Y YEARS FROM NOW = (Y-12)/2 +Y = 3y/2-6

my answer is D
Senior Manager
Senior Manager
avatar
Joined: 20 Feb 2006
Posts: 375
Followers: 1

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

GMAT Tests User
 [#permalink] New post 17 Sep 2006, 03:05
D) 3y/2 - 6

Same working as above
Intern
Intern
avatar
Joined: 17 Apr 2006
Posts: 42
Followers: 0

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

Re: Math Question driving me nuts!!! Please help [#permalink] New post 17 Sep 2006, 10:11
axl169 wrote:
The sum of Doris and Fred's ages is y. Doris is 12 years older than Fred. How many years old will Fred be y years from now, in terms of y.
A. y-6
b. 2y-6
C. y/2-6
D. 3y/2-6
E. 5y/2-6

I have the answer by plugging in numbers, but can't figure out how this formula came about. Any help would be greatly appreciated. Thanks.


Ans: D

Here'z how:

d + f = y, and d = f + 12, (d and f are ages of Doris and Fred)

therefore: 2f + 12 = y or f = (y-12)/2 --- (1)

Fred's age, y years from now is f + 12
= y/2 -6 + y
= 3y/2 - 6
Senior Manager
Senior Manager
User avatar
Joined: 28 Aug 2006
Posts: 302
Followers: 10

Kudos [?]: 72 [0], given: 0

GMAT Tests User
Re: Math Question driving me nuts!!! Please help [#permalink] New post 17 Sep 2006, 20:08
axl169 wrote:
The sum of Doris and Fred's ages is y. Doris is 12 years older than Fred. How many years old will Fred be y years from now, in terms of y.
A. y-6
b. 2y-6
C. y/2-6
D. 3y/2-6
E. 5y/2-6

I have the answer by plugging in numbers, but can't figure out how this formula came about. Any help would be greatly appreciated. Thanks.


Folks, again different ways were given to answer this.
But where is our faster method i.e giving some values and then proceeding...

Let F=24 Clearly D = 36, this mean y=60
After y years ie after 60 years F= 24+60 = 84.

Go to options.........
Placing y=60 Option D gives us 84.
So it is D.........

I recommend all of u to get into these methods

Regards,
_________________

Averages Accelerated:Guide to solve Averages Quickly(with 10 practice problems)


Last edited by cicerone on 25 Sep 2008, 00:25, edited 1 time in total.
Director
Director
User avatar
Joined: 28 Dec 2005
Posts: 761
Followers: 1

Kudos [?]: 8 [0], given: 0

GMAT Tests User
Re: Math Question driving me nuts!!! Please help [#permalink] New post 17 Sep 2006, 22:41
axl169 wrote:
The sum of Doris and Fred's ages is y. Doris is 12 years older than Fred. How many years old will Fred be y years from now, in terms of y.
A. y-6
b. 2y-6
C. y/2-6
D. 3y/2-6
E. 5y/2-6

I have the answer by plugging in numbers, but can't figure out how this formula came about. Any help would be greatly appreciated. Thanks.


d+f=y
d=f+2
=>2f+12=y
=>f = (y-12)/2
f+y = (y-12)/2+y = 3y/2 -6

D
Director
Director
avatar
Joined: 06 Sep 2006
Posts: 746
Followers: 1

Kudos [?]: 14 [0], given: 0

GMAT Tests User
 [#permalink] New post 19 Sep 2006, 11:43
D + F = Y; D = 12 + F; => 12 + F + F = Y => 2F = Y - 12

=> F = (Y - 12)/2

After Y years:
F = (Y - 12)/2 + Y => (Y -12 + 2Y)/2 => (3Y - 12)/2

=> 3Y/2 - 6. So D is my choice.
  [#permalink] 19 Sep 2006, 11:43
    Similar topics Author Replies Last post
Similar
Topics:
5 Experts publish their posts in the topic The sum of the ages of Doris and Fred is y years. If Doris Bunuel 8 24 Feb 2014, 23:07
1 In February 1995, Doris Schopper became president of the guerrero25 1 17 Dec 2013, 19:14
Danny, Doris and Dolly flipped a coin 5 times and each time IrinaOK 2 22 Sep 2007, 08:33
Danny, Doris and Dolly flipped a coin 5 times and each time sperumba 7 26 Jan 2006, 17:37
Danny, Doris and Dolly flipped a coin 5 times and each time cloaked_vessel 5 13 Mar 2005, 13:07
Display posts from previous: Sort by

The sum of Doris and Fred's ages is y . Doris is 12 years

  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®.