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.

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Re: DS absolute value [#permalink]
21 Aug 2007, 10:48

gmatiscoming wrote:

Is it true that ? |b-2|+|b+8|=10

(1) b less than or equal to 2 (2) b is greater than or equal to negative 8

C.

These type of questions, it is much faster if you realize the critical points of the equation. In this case, critical points are b=2 and b=-8.
From this, you know that there are three intervals that the equation must satisfy.

A interval: b<-8
B interval: -8<b<2
C interval: b>2

If you find that b fall into one of these interval, then it must be right. (1) doesn't since it falls into intervals A and B, so INSUFFICIENT. (2) doesn't either because it falls into interval B and C, INSUFFICIENT. Together, it falls into interval B. SUFFICIENT.

Re: DS absolute value [#permalink]
21 Aug 2007, 11:21

gmatiscoming wrote:

Is it true that ? |b-2|+|b+8|=10

(1) b less than or equal to 2 (2) b is greater than or equal to negative 8

C.

These type of questions, it is much faster if you realize the critical points of the equation. In this case, critical points are b=2 and b=-8.
From this, you know that there are three intervals that the equation must satisfy.

A interval: b<-8
B interval: -8<b<2
C interval: b>2

If you find that b fall into one of these interval, then it must be right. (1) doesn't since it falls into intervals A and B, so INSUFFICIENT. (2) doesn't either because it falls into interval B and C, INSUFFICIENT. Together, it falls into interval B. SUFFICIENT.

*Additional comment: for this method to be useful, you should at least plug in a value from those interval to see if which one equals 10.

If I can only freakin add on D day..arrrgggggggh...

guys any suggestions on how to avoid such mistakes????

It happens to me too when I try to do it too fast or do it at work. I suggest writing it out step by step or get a good sleep. Or maybe it is just rainy today :D

Re: DS absolute value [#permalink]
21 Aug 2007, 18:19

bkk145 wrote:

These type of questions, it is much faster if you realize the critical points of the equation. In this case, critical points are b=2 and b=-8. From this, you know that there are three intervals that the equation must satisfy.

A interval: b<-8 B interval: -8<b<2>2

If you find that b fall into one of these interval, then it must be right. (1) doesn't since it falls into intervals A and B, so INSUFFICIENT. (2) doesn't either because it falls into interval B and C, INSUFFICIENT. Together, it falls into interval B. SUFFICIENT.

Many thanks!

I also got C on this question =( But your explanation is great, it'll be definitely a shortcut for me!

gmatclubot

Re: DS absolute value
[#permalink]
21 Aug 2007, 18:19