Hello..
I am not a regular here, so, I am not sure if I am allowed to 'try' and post answers even if am not sure about an approach. Please remove my post if it violates rules, apologies!
Anyway, factoring 770 would result in the factors being 11, 7, 5 and 2. From the question, since 1 < w < x < y < z, w and z need to be 2 and 11. So, if that's correct, then w + z should be 13..
Bullzi
Question 3
This topic has expert replies
Source: Beat The GMAT — Problem Solving |
-
GMATGuruNY
- 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
770 = 2*5*7*11.oquiella wrote:3. If the product of the integers w,x,y, and z is 770, and if 1 < w < x < y < z, what is the value of w + z?
A. 10
B. 13
C. 16
D. 18
E. 21
Since wxyz = 770 and 1<w<x<y<z, w=2, x=5, y=7 and z=11.
Thus, w+z = 2+11 = 13.
The correct answer is B.
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
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
GMATGuruNY wrote:770 = 2*5*7*11.oquiella wrote:3. If the product of the integers w,x,y, and z is 770, and if 1 < w < x < y < z, what is the value of w + z?
A. 10
B. 13
C. 16
D. 18
E. 21
Since wxyz = 770 and 1<w<x<y<z, w=2, x=5, y=7 and z=11.
Thus, w+z = 2+11 = 13.
The correct answer is B.
How Did you factor 770 so quickly?
GMAT/MBA Expert
-
Brent@GMATPrepNow
- GMAT Instructor
- Posts: 16207
- Joined: Mon Dec 08, 2008 6:26 pm
- Location: Vancouver, BC
- Thanked: 5254 times
- Followed by:1268 members
- GMAT Score:770
Here's a free video on how to find the prime factorization of a number: https://www.gmatprepnow.com/module/gmat- ... /video/825oquiella wrote: How Did you factor 770 so quickly?
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
GMAT/MBA Expert
-
[email protected]
- Elite Legendary Member
- Posts: 10392
- Joined: Sun Jun 23, 2013 6:38 pm
- Location: Palo Alto, CA
- Thanked: 2867 times
- Followed by:511 members
- GMAT Score:800
Hi oquiella,
One of the great aspects of the 'math' behind factoring is that you can do the factoring in any order and you'll still get to the same result...
With 770, a few Number Properties stand out, so your first 'factor' would likely either be 2 (since 770 is EVEN), 7 (since 7 divides into 700 and 70) or 10 (since 770 ends in a 0). Let's go for the biggest option first....10
770 = (77)(10)
From here, you can further break down each of the two 'pieces'....
77 = (7)(11)
10 = (2)(5)
770 = (2)(5)(7)(11)
GMAT assassins aren't born, they're made,
Rich
One of the great aspects of the 'math' behind factoring is that you can do the factoring in any order and you'll still get to the same result...
With 770, a few Number Properties stand out, so your first 'factor' would likely either be 2 (since 770 is EVEN), 7 (since 7 divides into 700 and 70) or 10 (since 770 ends in a 0). Let's go for the biggest option first....10
770 = (77)(10)
From here, you can further break down each of the two 'pieces'....
77 = (7)(11)
10 = (2)(5)
770 = (2)(5)(7)(11)
GMAT assassins aren't born, they're made,
Rich
