GRE Prep 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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
If mn < 0 and k/m + l/n < mn, which of the following must be true?
[#permalink]
12 Aug 2018, 09:59
12 Aug 2018, 09:59
2
Expert Reply
5
Bookmarks
00:00
Question Stats:
66% (01:16) correct
33% (01:57) wrong based on 120 sessions
Hide Show timer Statistics
If \(mn < 0\) and \(\frac{k}{m} + \frac{l}{n} < mn\), which of the following must be true ?
(A) \(km + ln < (mn)^2\)
(B) \(kn + lm < 1\)
(C) \(kn + lm > (mn)^2\)
(D) \(k + l > mn\)
(E) \(km > –ln\)
(A) \(km + ln < (mn)^2\)
(B) \(kn + lm < 1\)
(C) \(kn + lm > (mn)^2\)
(D) \(k + l > mn\)
(E) \(km > –ln\)
Re: If mn < 0 and k/m + l/n < mn, which of the following must be true?
[#permalink]
18 Nov 2018, 16:25
18 Nov 2018, 16:25
Explain please.
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: If mn < 0 and k/m + l/n < mn, which of the following must be true?
[#permalink]
19 Nov 2018, 07:32
19 Nov 2018, 07:32
3
Carcass wrote:
If \(mn < 0\) and \(\frac{k}{m} + \frac{l}{n} < mn\), which of the following must be true ?
(A) \(km + ln < (mn)^2\)
(B) \(kn + lm < 1\)
(C) \(kn + lm > (mn)^2\)
(D) \(k + l > mn\)
(E) \(km > –ln\)
(A) \(km + ln < (mn)^2\)
(B) \(kn + lm < 1\)
(C) \(kn + lm > (mn)^2\)
(D) \(k + l > mn\)
(E) \(km > –ln\)
GIVEN: \(\frac{k}{m} + \frac{l}{n} < mn\)
Rewrite fractions with common denominator: \(\frac{kn}{mn} + \frac{lm}{mn} < mn\)
Combine fractions: \(\frac{kn+lm}{mn} < mn\)
Multiply both sides of inequality by \(mn\) to get: \(kn+lm > (mn)^2\)
ASIDE: Since we're told that \(mn < 0\), we REVERSED the direction of the inequality symbol, because in the last step, we multiplied both sides by a NEGATIVE value.
Answer: C
RELATED VIDEO
