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

Redeem

help solving this geometry problem

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 10
Joined: Sun Aug 02, 2009 6:22 am

help solving this geometry problem

by elemat » Thu Oct 08, 2009 4:11 pm
Hi Everyone,

I ran across this problem. What is the fastest way to solve this problem, without mapping anything out...

IN a xy-coordinate plane, a line is defined by y=kx+1. If (4,b), (a,4) and (a,b+1) are three points on the line, where a and b are unknown, the k =
a. 1/2
b. 1
c. 1.5
d. 2
e. 2.5

Thanks!
Top
Source: — Problem Solving |
Master | Next Rank: 500 Posts
Posts: 399
Joined: Wed Apr 15, 2009 3:48 am
Location: india
Thanked: 39 times

by xcusemeplz2009 » Thu Oct 08, 2009 7:53 pm
b=4k+1
4=ak+1
b+1=ak+1
solving
k=1/2
It does not matter how many times you get knocked down , but how many times you get up
Top
Master | Next Rank: 500 Posts
Posts: 128
Joined: Thu Jul 30, 2009 1:46 pm
Thanked: 1 times

by fruti_yum » Sun Oct 11, 2009 10:58 am
xcusemeplz2009 wrote:b=4k+1
4=ak+1
b+1=ak+1
solving
k=1/2
dont get it! it seems too complicated!!
Top
Junior | Next Rank: 30 Posts
Posts: 27
Joined: Thu Jul 23, 2009 6:29 am
Thanked: 3 times

by aa2kash » Mon Oct 12, 2009 5:04 am
fruti_yum wrote:
xcusemeplz2009 wrote:b=4k+1
4=ak+1
b+1=ak+1
solving
k=1/2
dont get it! it seems too complicated!!
As per the question there are 3 points which are lying on the line,so they must satisfy the equation of the line. Putting the values we get
b=4k+1 --1
4=ak+1 ---2
b+1=ak+1 ----3

from 2 and 3, right hand side is same i.e ak+1
therefore b+1=4 ..> b=3
Substituting in equation 1, we get
3=4k+1
2=4k
1/2=k
Top
Post new topic Post Reply
• Page 1 of 1