problem solving

This topic has expert replies
Master | Next Rank: 500 Posts
Posts: 162
Joined: Mon Jul 28, 2008 8:33 pm
Location: San Jose,CA
Thanked: 1 times

problem solving

by ddm » Mon Aug 04, 2008 2:20 pm
Joan, Kylie, Lillian, and Miriam all celebrate their birthdays today. Joan is 2 years younger than Kylie, Kylie is 3 years older than Lillian, and Miriam is one year older than Joan. Which of the following could be the combined age of all four women today?
A.51
B.52
C.53
D.54
E.55
Source: — Problem Solving |

Newbie | Next Rank: 10 Posts
Posts: 7
Joined: Fri Mar 28, 2008 3:57 pm

by singhr10 » Mon Aug 04, 2008 6:18 pm
we have the following equations.
J = K-2
K= 3+L
M = 1+J

J+K+L+M = SUM OF AGE

K-2 +K+L+1+J
K-2 +K-2+3+L+J= SUM
K-2+K-2+K+K-2 = SUM (SUB FOR J AND K)
4K-6 =SUM

FROM THE BELOW OPTIONS
4K = 6+54 (SINCE THIS OPTION WILL ONLY BE DIVISIBLE BY 4

K= 60/4 = 15
Hence ans is 54....

User avatar
Newbie | Next Rank: 10 Posts
Posts: 9
Joined: Thu Sep 15, 2011 9:41 am

by JohnRapp » Mon Nov 21, 2011 6:45 pm
ddm wrote:Joan, Kylie, Lillian, and Miriam all celebrate their birthdays today. Joan is 2 years younger than Kylie, Kylie is 3 years older than Lillian, and Miriam is one year older than Joan. Which of the following could be the combined age of all four women today?
A.51
B.52
C.53
D.54
E.55
First set up the relationships into equations:
J=K+2
K=L+3
M=J+1

Given these relationships, I ordered them from youngest to oldest with the difference in between.
L +3 K +2 J +1 M +0

The sum of the differences in relationships = 6.

The only age divisible by 6 is [spoiler]D (54)[/spoiler]

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pm
Location: Milpitas, CA
Thanked: 1854 times
Followed by:523 members
GMAT Score:770

by Anurag@Gurome » Mon Nov 21, 2011 9:28 pm
ddm wrote:Joan, Kylie, Lillian, and Miriam all celebrate their birthdays today. Joan is 2 years younger than Kylie, Kylie is 3 years older than Lillian, and Miriam is one year older than Joan. Which of the following could be the combined age of all four women today?
A.51
B.52
C.53
D.54
E.55
Say, age of Kylie is n years.
=> Age of Joan is (n - 2) years
=> Age of Lilian is (n - 3) years
=> Age of Miriam is (n - 1) years

Hence, total age = (4n - 6) years

Hence, the total age must be 6 less than an integer multiple of 4, i.e. 2 less than an integer multiple of 4. Only such option is 54.

Hence, the correct answer is D.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/

Junior | Next Rank: 30 Posts
Posts: 20
Joined: Sun Apr 17, 2011 7:16 am
Followed by:1 members

by chaitanyabhansali » Tue Nov 22, 2011 10:37 am
Joan, Kylie, Lillian, and Miriam all celebrate their birthdays today. Joan is 2 years younger than Kylie, Kylie is 3 years older than Lillian, and Miriam is one year older than Joan. Which of the following could be the combined age of all four women today?
A.51
B.52
C.53
D.54
E.55

Answer:

Let lillian's age be x today.
then, joan's age = x+1, kylie's age = x+3 and Miriam's age = x+2.

combined age = x+x+1+x+2+x+3 = 4x+6

Put the expression equal to given options one by one.

Only option 'D' i.e 54 satisfies the equation i.e when x comes out to be an integer.

4x+6 = 54
=> 4x = 48
=> x = 12

IMO: D

User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Tue Nov 22, 2011 11:50 am
ddm wrote:Joan, Kylie, Lillian, and Miriam all celebrate their birthdays today. Joan is 2 years younger than Kylie, Kylie is 3 years older than Lillian, and Miriam is one year older than Joan. Which of the following could be the combined age of all four women today?
A.51
B.52
C.53
D.54
E.55
We can guess and check VERY quickly.
Given the answer choices, the average age must be around 52/4 = 13.

Let J = 13.
Then:
K = J+2 = 15.
L = K-3 = 12.
M = J+1 = 14.
Sum = 13+15+12+14 = 54.

The correct answer is D.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3

User avatar
Master | Next Rank: 500 Posts
Posts: 296
Joined: Sun May 29, 2011 5:10 am
Location: Vietnam
Thanked: 10 times
Followed by:5 members

by tuanquang269 » Tue Nov 22, 2011 8:26 pm
+ 1 for D