Last visit was: 22 Apr 2026, 13:28 It is currently 22 Apr 2026, 13:28
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.
Close
Request Expert Reply
Confirm Cancel
User avatar
udribat
Joined: 12 Jul 2006
Last visit: 15 Nov 2008
Posts: 6
Own Kudos:
Posts: 6
Kudos: 240
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
mbajingle
Joined: 30 Oct 2008
Last visit: 07 Oct 2009
Posts: 12
Own Kudos:
Posts: 12
Kudos: 2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
scthakur
Joined: 17 Jun 2008
Last visit: 30 Jul 2009
Posts: 608
Own Kudos:
Posts: 608
Kudos: 453
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
amitdgr
Joined: 30 Jun 2008
Last visit: 21 May 2013
Posts: 534
Own Kudos:
Given Kudos: 1
Posts: 534
Kudos: 3,211
Kudos
Add Kudos
Bookmarks
Bookmark this Post
scthakur

The equation above should be 20n^2 +mn - m^2 = 0
From the equation above, (5n-m)(4n+m) = 0

how do we factor such equations 20n^2 +mn - m^2 = 0? I got stuck on this step....
User avatar
mbajingle
Joined: 30 Oct 2008
Last visit: 07 Oct 2009
Posts: 12
Own Kudos:
Posts: 12
Kudos: 2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
amitdgr
scthakur

The equation above should be 20n^2 +mn - m^2 = 0
From the equation above, (5n-m)(4n+m) = 0

how do we factor such equations 20n^2 +mn - m^2 = 0? I got stuck on this step....

Two solutions of quadratic equation of form
a(x^2) + bx + c = 0, where a, b and c are constants,are

x = (-b + sqrt(b^2 -4ac))/2a
x = (-b - sqrt(b^2 - 4ac))/2a
User avatar
amitdgr
Joined: 30 Jun 2008
Last visit: 21 May 2013
Posts: 534
Own Kudos:
Given Kudos: 1
Posts: 534
Kudos: 3,211
Kudos
Add Kudos
Bookmarks
Bookmark this Post
mbajingle
amitdgr
scthakur

The equation above should be 20n^2 +mn - m^2 = 0
From the equation above, (5n-m)(4n+m) = 0

how do we factor such equations 20n^2 +mn - m^2 = 0? I got stuck on this step....

Two solutions of quadratic equation of form
a(x^2) + bx + c = 0, where a, b and c are constants,are

x = (-b + sqrt(b^2 -4ac))/2a
x = (-b - sqrt(b^2 - 4ac))/2a

so here a = 20, b = m and c = -m² ???
User avatar
bigtreezl
Joined: 23 May 2008
Last visit: 30 Jul 2009
Posts: 364
Own Kudos:
Posts: 364
Kudos: 191
Kudos
Add Kudos
Bookmarks
Bookmark this Post
m/n=20n/m-n = m/1=20/m-n

m^2-mn=20 = m(m-n)=20 so 5(5-1)=20 m/n =5:1
User avatar
amitdgr
Joined: 30 Jun 2008
Last visit: 21 May 2013
Posts: 534
Own Kudos:
Given Kudos: 1
Posts: 534
Kudos: 3,211
Kudos
Add Kudos
Bookmarks
Bookmark this Post
bigtreezl
m/n=20n/m-n = m/1=20/m-n
m^2-mn=20 = m(m-n)=20 so 5(5-1)=20 m/n =5:1


Bigtreez .... where did "n" go ??



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Problem Solving (PS) Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
Moderator:
Math Expert
109754 posts