Absolute Value Questions

[log2bala]

Hello Guys


Well, I am confused in the Absolute Value questions, as I am not sure how to tackle them. this was one of the questions which was in the CAT exam

1. Is I x I > 1?
a) I x+1 I = 2 Ix - 1I
b) I x - 3 I > 0

Answer: ( IxI means only x, but in this case it is asking Is x > 1 and - x > 1 ( How would you rephrase this part, would this be x < - 1 ? So the question would be is x between -1 and 1 right.

( Not so sure on this part above)

Taking B as the option.

I) x - 3 > 0
x - 3 +3>0+3
x>3
( Certainly B is not sufficient to answer the question) So BD is rules out


Now Taking A as the other option Ix+1I = 2 Ix - 1I

II) Taking both sides of the absolute value as +ve

x + 1 = 2 (x - 1)
Solving for x we get x = 3 -----> Which does not satisfy the question

Going at the extreme end and taking both sides as -ve

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

here we get x = - 3 ------> which also does not satisfy the question


Now, taking the both sides , Here is where I get confused? How will take both the options and work towards the problem ?


Second Problem

2. Is IaI > IbI ?

a) b < - a
b) a < 0

Answer.

Taking Option B again and eliminating it as it does not have any information on BD is crossed out

Taking Option A now, How do you rephrase this inequality? b < -a

Please clarify on these types how to approach them?

Thank you guys for your help

Bala

[RonPurewal]

hi -

here's a thread on the first problem:
absolute-value-question-bank-t3648.html

please post OVER THERE if you have any remaining questions.

--

as for the second problem, the forum rules stipulate that only one problem be posted per thread.

so please create a new thread with that problem, and then we'll address that new thread.

thanks.