GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 26 Apr 2019, 08:58

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

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

Is the slope of the line l equal to -1/5?

Author Message
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 54696
Is the slope of the line l equal to -1/5?  [#permalink]

Show Tags

25 Jul 2017, 03:59
1
3
00:00

Difficulty:

65% (hard)

Question Stats:

51% (01:29) correct 49% (01:11) wrong based on 85 sessions

HideShow timer Statistics

Is the slope of the line l equal to -1/5?

(1) Lines m and n are parallel and sum of their slopes is less than 1/2.
(2) Line l is perpendicular to line m.

_________________
Intern
Joined: 29 May 2017
Posts: 3
Is the slope of the line l equal to -1/5?  [#permalink]

Show Tags

25 Jul 2017, 04:58
3
1. The slope of line m and n has to be less than 1/4. Not sufficient.

2. If l and m are perpendicular, the product of their slope should be equal to -1 and for the slope of l to be -1/5 , the slope of m should be equal to 5 but no info on that. Not sufficient.

However, taking 1 and 2 combined, we are certain that slope of m can never be 5 so the slope of l can never be -1/5.

Hence, I go with C.

Kudos, if agree.
Current Student
Joined: 18 Aug 2016
Posts: 619
Concentration: Strategy, Technology
GMAT 1: 630 Q47 V29
GMAT 2: 740 Q51 V38
Re: Is the slope of the line l equal to -1/5?  [#permalink]

Show Tags

25 Jul 2017, 22:22
Bunuel wrote:
Is the slope of the line l equal to -1/5?

(1) Lines m and n are parallel and sum of their slopes is less than 1/2.
(2) Line l is perpendicular to line m.

(1) Let slope be m and n for respective lines
$$m=n$$
$$m+m<1/2$$
$$m<1/4$$
not sufficient

(2) $$l*m = -1$$
not sufficient

on combining
$$m=-1/l$$
$$-1/l<1/4$$
$$1/l>1/4$$
$$0<l<4$$
Sufficient

Hence C
_________________
We must try to achieve the best within us

Thanks
Luckisnoexcuse
Senior Manager
Joined: 29 Jun 2017
Posts: 454
GPA: 4
WE: Engineering (Transportation)
Re: Is the slope of the line l equal to -1/5?  [#permalink]

Show Tags

29 Aug 2017, 01:14
Luckisnoexcuse wrote:
Bunuel wrote:
Is the slope of the line l equal to -1/5?

(1) Lines m and n are parallel and sum of their slopes is less than 1/2.
(2) Line l is perpendicular to line m.

(1) Let slope be m and n for respective lines
$$m=n$$
$$m+m<1/2$$
$$m<1/4$$
not sufficient

(2) $$l*m = -1$$
not sufficient

on combining
$$m=-1/l$$
$$-1/l<1/4$$
$$1/l>1/4$$
$$0<l<4$$
Sufficient

Hence C

can u elaborate how come

−1/l<1/4
1/l>1/4

i think 1/L > -1/4
if u are multiplying with -ve on both sides

??
_________________
Give Kudos for correct answer and/or if you like the solution.
Senior Manager
Joined: 29 Jun 2017
Posts: 454
GPA: 4
WE: Engineering (Transportation)
Re: Is the slope of the line l equal to -1/5?  [#permalink]

Show Tags

29 Aug 2017, 01:22
Ans is C:

1) insufficient as does not tell us about slope of l
2) insufficient no info about m

combining both

m= -1/L
and also m+m < 1/2
m<1/4

ie -1/L < 1/4
therefore L can take values (-infinity, -4) U (0, + infinity)

Clearly L can not take value from -4 to 0 therefore the slope can never be -1/5
Definite NO

_________________
Give Kudos for correct answer and/or if you like the solution.
Re: Is the slope of the line l equal to -1/5?   [#permalink] 29 Aug 2017, 01:22
Display posts from previous: Sort by