Least possible value of x

This topic has expert replies
Source: — Problem Solving |

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 » Sat Dec 01, 2012 4:53 am
neeti2711 wrote:If x,y and z are positive integers and 3x=4y=7z, then the least possible value of x+y+z is

(A) 33
(B) 40
(C) 49
(D) 61
(E) 84
Let 3x=4y=7z = n. Then x = n/3, y = n/4 and z = n/7
x+y+z = n/3 + n/4 + n/ 7 = 61n/84
Since x , y and z are positive integers so x + y + z should also be a positive integer, this implies minimum value of n = 84
Hence, minimum value of x + y + z = 61

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/

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 » Sat Dec 01, 2012 6:05 am
neeti2711 wrote:If x,y and z are positive integers and 3x=4y=7z, then the least possible value of x+y+z is

(A) 33
(B) 40
(C) 49
(D) 61
(E) 84
3x = 4y = 7z.
Minimum possible solution:
3(4*7) = 4(3*7) = 7(3*4).
Thus, x+y+z = (4*7) + (3*7) + (3*4) = 28+21+12 = 61.

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