Best Approach to solve Inequlity type of Questions

This topic has expert replies
Source: — Problem Solving |

Master | Next Rank: 500 Posts
Posts: 110
Joined: Sun May 25, 2008 3:45 pm

by ajmoney09 » Wed Jul 16, 2008 9:07 pm
I think the best way is to plug numbers in and check, best way to do it. They need some getting use to.

for statement (1) I tried:
m-3(z) >0

7-3(2)>0, which makes this statement true....Plugging back into m+z>0? you get 7+2, which says answers "Yes"....But the main error with plugging numbers is that you can usually have more than one answer.

So pick 2 different numbers making sure the statement still stays true; try, 5-3(- 8 ) > 0 Which makes this statement true, but plugging back into the questions you get 5+-8 > 0 Which answers "NO."

The same problem applies for both statements, there are multiple ways to make the statements true, but make the question answer be "no" or "Yes."

Hope this helped,
Aj.
Last edited by ajmoney09 on Wed Jul 16, 2008 9:22 pm, edited 2 times in total.

Junior | Next Rank: 30 Posts
Posts: 22
Joined: Mon Apr 14, 2008 3:36 pm
Location: California
Thanked: 1 times

by TRANGZON » Wed Jul 16, 2008 9:21 pm
(1) m-3z>0 --> m>3z --> insuff

(2) 4z-m>0 --> insuff

(1) + (2) --> m - 3z + 4z - m > 0 --> z>0
(1) m>3z
-> m>0
--> m+z >0
--> C
What is OA?

Legendary Member
Posts: 829
Joined: Mon Jul 07, 2008 10:09 pm
Location: INDIA
Thanked: 84 times
Followed by:3 members

by sudhir3127 » Wed Jul 16, 2008 10:56 pm
my answer is C.

adding statement 1 and 2 we get Z>0 -------------------i

statement 1 says m- 3Z>0 which mean m>3Z -------------------ii

that means m>0

hence m+Z>0

Newbie | Next Rank: 10 Posts
Posts: 9
Joined: Tue May 27, 2008 4:14 am
Thanked: 1 times

by Amitk101 » Wed Jul 16, 2008 11:50 pm
Thanks everyone for the solution.

OA is C.