BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

If m and n are nonzero and such that mn+n = m , which of the

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
GMAT Instructor
Posts: 1449
Joined: Sat Oct 09, 2010 2:16 pm
Thanked: 59 times
Followed by:33 members

If m and n are nonzero and such that mn+n = m , which of the

by fskilnik@GMATH » Mon Sep 17, 2018 2:34 pm

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

If m and n are nonzero and such that mn+n = m , which of the following is equal to the difference between the reciprocal of m and the reciprocal of n (in that order)?

(A) the opposite of mn
(B) the reciprocal of mn
(C) the opposite of 1
(D) the reciprocal of 1
(E) none above

Answer: [spoiler]__(C)___[/spoiler]
Difficulty: 600-650 Level
Source: www.gmath.net
Fabio Skilnik :: GMATH method creator ( Math for the GMAT)
English-speakers :: https://www.gmath.net
Portuguese-speakers :: https://www.gmath.com.br
Top
Source: — Problem Solving |
User avatar
GMAT Instructor
Posts: 1449
Joined: Sat Oct 09, 2010 2:16 pm
Thanked: 59 times
Followed by:33 members

by fskilnik@GMATH » Tue Sep 18, 2018 8:14 am
fskilnik wrote:If m and n are nonzero and such that mn+n = m , which of the following is equal to the difference between the reciprocal of m and the reciprocal of n (in that order)?

(A) the opposite of mn
(B) the reciprocal of mn
(C) the opposite of 1
(D) the reciprocal of 1
(E) none above
\[m,n\,\, \ne 0\]
\[mn + n = m\]
\[? = \frac{1}{m} - \frac{1}{n} = \frac{n}{{mn}} - \frac{m}{{nm}} = \frac{{n - m}}{{nm}}\,\,\mathop = \limits^{\left( * \right)} \,\,\frac{{ - mn}}{{nm}} = - 1\]
\[\left( * \right)\,\,\,mn + n = m\,\,\,\,\, \Rightarrow \,\,\,n - m = - mn\]
The right answer is therefore (C), because -1 is the opposite of 1.


This solution follows the notations and rationale taught in the GMATH method.

Regards,
Fabio.
Fabio Skilnik :: GMATH method creator ( Math for the GMAT)
English-speakers :: https://www.gmath.net
Portuguese-speakers :: https://www.gmath.com.br
Top
Post new topic Post Reply
• Page 1 of 1