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

Redeem

the line n

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

the line n

by sanju09 » Tue May 26, 2009 12:55 am
What is the equation of line n?

(1) The point (6, 8) is on line n.

(2) Sum of the intercepts of the line n, on the coordinate axes is 28.



MBM
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Top
Source: — Data Sufficiency |
Master | Next Rank: 500 Posts
Posts: 418
Joined: Wed Jun 11, 2008 5:29 am
Thanked: 65 times

by bluementor » Tue May 26, 2009 2:04 am
y intercept = c
x intercept = b
slope of line = m

what is the equation of line n?

statement 1: the point (6, 8) is on line n

clearly insufficient, since you would need either the slope or another known point on the line to determine the equation.

statement 2: b + c = 28

actuall values of b and c are unknown. insufficient.

for eg.,

if b = 20, c = 8, the slope = -8/28
if b = 8, c = 20, the slope = -20/8

both statements together:

b + c = 28
b = 28 - c

equation of a straight line : y = mx + c

and the slope, m = -c/b = -c/(28 - c) = c/(c - 28)

so, y = (c/(c - 28))*x + c

we know from statement 1 that line n passes through (6,8). Substituting values for x and y respectively:

8 = (c/(c - 28))*(6) + c
8 - c= (6c)/(c - 28)
c^2 - 30c + 28(8) = 0
c^2 - 30c + 14(16) = 0
(c - 14)(c-16) = 0

c = 14 or c = 16.

if c = 14, b = 28 - 14 = 14, m = -1
if c = 16, b = 28 - 16 = 12, m = -4/3

insufficient since there are two possible slopes.

choose E.

-BM-
Top
Master | Next Rank: 500 Posts
Posts: 371
Joined: Fri Mar 06, 2009 2:48 am
Thanked: 27 times
GMAT Score:740

by 2010gmat » Tue May 26, 2009 2:39 am
1. In suff
2. In suff

1 + 2 ...

x/a + y/b = 1; intercept eqn of line

x/a + y/(28-a) = 1; use 1. to solve for a ...

1+2 = suff --> C
Top
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

by sanju09 » Tue May 26, 2009 2:51 am
2010gmat wrote:1. In suff
2. In suff

1 + 2 ...

x/a + y/b = 1; intercept eqn of line

x/a + y/(28-a) = 1; use 1. to solve for a ...

1+2 = suff --> C
Will you get a single value of a in this case, 2010gmat?
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Top
Post new topic Post Reply
• Page 1 of 1