Events & Promotions
|
|
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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Apr 2610:00 AM EDT
-11:00 AM EDT
The Target Test Prep course represents a quantum leap forward in GMAT preparation, a radical reinterpretation of the way that students should study. Try before you buy with a 5-day, full-access trial of the course for FREE!
Apr 2711:00 AM EDT
-12:00 PM EDT
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors
Apr 2808:00 AM PDT
-11:00 AM PDT
Whether you are just beginning your MBA journey or fine-tuning your path to a 700+ score, GMAT Day is designed to give you a competitive edge.
06 Sep 2018, 00:38
Kudos
Bookmarks
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
35%
(medium)
Question Stats:
58% (00:57) correct
42%
(01:01)
wrong
based on 152
sessions
History
Date
Time
Result
Not Attempted Yet
If line m is perpendicular to line l and line l passes through points (6, 5) and (6, 8), what is the slope of line m?
A. -1
B. 0
C. 1
D. the slope is undefined
E. the slope cannot be determined from the information given
A. -1
B. 0
C. 1
D. the slope is undefined
E. the slope cannot be determined from the information given
06 Sep 2018, 01:19
Kudos
Bookmarks
Bunuel
slope of line l =\(\frac{y2-y1}{x2-x1}\) = 3/0 (undefined )
since line l and m are perpendicular
slope of l * slope of m = -1
slope of m = \(\frac{-1}{(3/0)}\)= 0
07 Sep 2018, 13:35
Kudos
Bookmarks
Bunuel
Solution
Line \(l\) is vertical.
Slope of line \(l\): \(\frac{rise}{run}=\frac{y_2-y_1}{x_2-x_1}=\frac{8-6}{5-5}=\frac{2}{0}\)
Any number divided by 0 is undefined.
Slope of line \(l\): undefined
Line \(m\) is perpendicular to line \(l\)
Generally, perpendicular lines have slopes that are negative reciprocals of one another. Not in this case.
We cannot calculate the negative reciprocal of an undefined number.
However, any horizontal line is perpendicular to any vertical line.
Line \(m\) is horizontal; the slope of a horizontal line = 0
Draw a horizontal line, pick two points, and calculate slope (see notes below)
Slope of line \(m = 0\)
Answer B
HOW TO REMEMBER WHICH LINE GETS WHICH SLOPE
To keep vertical and horizontal lines' slopes straight, use coordinates or a mnemonic
• Slope from coordinates
Line \(l\): (6, 5) and (6, 8)
Line \(m\): draw any horizontal line and pick two points.
From diagram, two points on Line \(m\): (1, 2) and (3, 2)
Slope of line \(m\): \(\frac{rise}{run}=\frac{y_2-y_1}{x_2-x_1}=\frac{2-2}{3-1}=\frac{0}{2}=0\)
Slope of line \(m=0\)
Slope of line \(l\): \(\frac{rise}{run}=\frac{y_2-y_1}{x_2-x_1}=\frac{8-6}{5-5}=\frac{2}{0}\)
Any number divided by 0 is undefined. Slope of line \(l\): undefined
• Use a mnemonic.
hOrizontal has a letter O
The letter O in hOrizontal looks like a zero, 0
A hOrizontal line has slope of 0
-- "Vertical," obviously, does not have the letter "O"
Other mnemonics
-- One very good site uses "neither positive nor negative number" and "no number that is both positive and negative." HERE
-- Another site uses the acronyms VUX and HOY , which are simple and effective, HERE
Attachment:
verthorzlines.jpg [ 43.33 KiB | Viewed 3666 times ]
