Last visit was: 12 Dec 2024, 00:48 It is currently 12 Dec 2024, 00:48
Close
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
Your Progress

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
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 11 Dec 2024
Posts: 97,825
Own Kudos:
685,188
 [1]
Given Kudos: 88,254
Products:
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 97,825
Kudos: 685,188
 [1]
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
User avatar
kumarparitosh123
Joined: 02 Nov 2015
Last visit: 19 Dec 2018
Posts: 132
Own Kudos:
Given Kudos: 121
GMAT 1: 640 Q49 V29
GMAT 1: 640 Q49 V29
Posts: 132
Kudos: 62
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
Nikkb
User avatar
Current Student
Joined: 02 Jul 2017
Last visit: 08 Jan 2024
Posts: 234
Own Kudos:
305
 [1]
Given Kudos: 70
Concentration: Entrepreneurship, Technology
GMAT 1: 730 Q50 V38
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
User avatar
niks18
User avatar
Retired Moderator
Joined: 25 Feb 2013
Last visit: 30 Jun 2021
Posts: 887
Own Kudos:
Given Kudos: 54
Location: India
GPA: 3.82
Products:
Posts: 887
Kudos: 1,619
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
If y is negative, what is the value of x ?

(1) x + y = -(|y| - x)
(2) x - y = 2

Statement 1: \(x+y = -|y|+x\). As \(y\) is negative hence \(y = -|y|\). So adding same value \(x\) to both sides of the equation will not change the value of the Equality \(y = -|y|\). Hence \(x\) can be any real number. Insufficient

Statement 2: Cannot be solved as we have two variable and one equation. Hence Insufficient

Combining 1 & 2. we cannot find the value of \(x\) as we have only one equation and two variables. Hence Insufficient

Option E
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,114
Own Kudos:
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,114
Kudos: 17,797
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
If y is negative, what is the value of x ?

(1) x + y = -(|y| - x)
(2) x - y = 2


Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

There 2 variables and 0 equation. Thus we need 2 equations to solve for the variables; the conditions provide 2 equations, so there is high chance that (C) will be the answer.


Condition 1) & 2)

\(x + y = -(|y| - x)\) is equivalent to \(x+y = -(-y-x)\) since y is negative.
Then we have \(x + y = x + y\).
We don't have any equation.

The only equation \(x - y = 2\) from the condition 2) is not sufficient.

Both conditions together, they are not sufficient.

Normally for cases where we need 2 more equations, such as original conditions with 2 variables, or 3 variables and 1 equation, or 4 variables and 2 equations, we have 1 equation each in both 1) and 2). Therefore C has a high chance of being the answer, which is why we attempt to solve the question using 1) and 2) together. Here, there is 70% chance that C is the answer, while E has 25% chance. These two are the key questions. In case of common mistake type 3,4, the answer may be from A, B or D but there is only 5% chance. Since C is most likely to be the answer according to DS definition, we solve the question assuming C would be our answer hence using 1) and 2) together. (It saves us time). Obviously there may be cases where the answer is A, B, D or E.
Moderator:
Math Expert
97825 posts