a+b+c=?
1) (a+b+c)^2=0
2) a^2+b^2+c^2=0
* A solution will be posted in two days.
5-Day Free Trial
5-day free, full-access trial TTP
Available with Beat the GMAT members only code
MORE DETAILS
a+b+c=?
This topic has expert replies
-
Max@Math Revolution
- Elite Legendary Member
- Posts: 3991
- Joined: Fri Jul 24, 2015 2:28 am
- Location: Las Vegas, USA
- Thanked: 19 times
- Followed by:37 members
Math Revolution
The World's Most "Complete" GMAT Math Course!
Score an excellent Q49-51 just like 70% of our students.
[Free] Full on-demand course (7 days) - 100 hours of video lessons, 490 lesson topics, and 2,000 questions.
[Course] Starting $79 for on-demand and $60 for tutoring per hour and $390 only for Live Online.
Email to : [email protected]
GMAT/MBA Expert
-
Brent@GMATPrepNow
- GMAT Instructor
- Posts: 16207
- Joined: Mon Dec 08, 2008 6:26 pm
- Location: Vancouver, BC
- Thanked: 5254 times
- Followed by:1268 members
- GMAT Score:770
Target question: What is the value of a + b + c?Max@Math Revolution wrote:a + b + c = ?
1) (a + b + c)² = 0
2) a² + b² + c² = 0
Statement 1: (a + b + c)² = 0
If SOMETHING² = 0, we can be certain that that SOMETHING = 0
So, in this case, we can be certain that a + b + c = 0
Since we can answer the target question with certainty, statement 1 is SUFFICIENT
Statement 2: a² + b² + c² = 0
RULE: If we square any value, the result will be GREATER THAN OR EQUAL TO ZERO
In other words, for all values of k, k² > 0
So, if a² + b² + c² = 0, we can conclude that a = 0, b = 0 and c = 0, which means a + b + c = 0
Since we can answer the target question with certainty, statement 2 is SUFFICIENT
Answer: D
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
-
Max@Math Revolution
- Elite Legendary Member
- Posts: 3991
- Joined: Fri Jul 24, 2015 2:28 am
- Location: Las Vegas, USA
- Thanked: 19 times
- Followed by:37 members
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.
a+b+c=?
1) (a+b+c)^2=0
2) a^2+b^2+c^2=0
In the original condition, there are 3 variables, which should match with the number of equations. So you need 3 equations. For 1) 1 equation, for 2) 1 equation, which requires 1 more equation. So, it is likely that E is the answer.
When 1) & 2), they become 1) a+b+c=0 2) a=b=c=0, which is eventually 1)=2). Therefore, the answer is D.
a+b+c=?
1) (a+b+c)^2=0
2) a^2+b^2+c^2=0
In the original condition, there are 3 variables, which should match with the number of equations. So you need 3 equations. For 1) 1 equation, for 2) 1 equation, which requires 1 more equation. So, it is likely that E is the answer.
When 1) & 2), they become 1) a+b+c=0 2) a=b=c=0, which is eventually 1)=2). Therefore, the answer is D.
Math Revolution
The World's Most "Complete" GMAT Math Course!
Score an excellent Q49-51 just like 70% of our students.
[Free] Full on-demand course (7 days) - 100 hours of video lessons, 490 lesson topics, and 2,000 questions.
[Course] Starting $79 for on-demand and $60 for tutoring per hour and $390 only for Live Online.
Email to : [email protected]
