Least Possible Value Problem

Expert replies

wcheng57: Junior | Next Rank: 30 Posts; Posts: 13; Joined: Tue Dec 08, 2009 1:09 am

by wcheng57 » Wed May 26, 2010 4:13 pm

If x, y, z are all 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

Can someone explain to me why D is the correct answer?

Like this post

Source: Beat The GMAT — Problem Solving | Wed May 26, 2010 4:13 pm

GMAT/MBA Expert

Rahul@gurome: GMAT Instructor; Posts: 1179; Joined: Sun Apr 11, 2010 9:07 pmFollowed by: 88 members; Location: Milpitas, CA; Thanked: 447 times

by Rahul@gurome » Wed May 26, 2010 4:23 pm

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).

Rahul Lakhani
Quant Expert
Gurome, Inc.
https://www.GuroMe.com
On MBA sabbatical (at ISB) for 2011-12 - will stay active as time permits
1-800-566-4043 (USA)
+91-99201 32411 (India)

Like this post

gmatjedi: Senior | Next Rank: 100 Posts; Posts: 85; Joined: Sat Aug 15, 2009 4:36 am; Thanked: 19 times

by gmatjedi » Thu May 27, 2010 2:50 am

need to find the lcm
lcm of 3, 4, 7 =84
divide 84 by 3, 4, and 7= 28, 21, 12
add those numbers=61

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

559 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review