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by manpsingh87 » Wed May 25, 2011 10:18 am
nafiul9090 wrote:is x between 0 and 1?
1) x^2 is less than 1
2) x^3 is positive



OA later
1) x^2<1;
x^2-1<0;
(x-1)(x+1)<0;
-1<x<1;
now x can assume both positive and negative values lying between -1 and 1; i.e. x can be either -0.5 or 0.7, as we can't say with surety whether x is lying between 0 and 1 hence 1 alone is not sufficient to answer the question.

2) x^3 is positive; i.e x>0; because now here x can either lie between 0 and 1 or it can be greater than 1 hence 2 alone is not sufficient to answer the question.

combining 1 and 2 we have;
from -1<x<1; and from 2 x>0;
therefore x will lie between 0<x<1;(because here we are looking for a common solution that will satisfy both 1 and 2) hence C
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by nafiul9090 » Wed May 25, 2011 10:34 am
manpsingh87 wrote:
nafiul9090 wrote:is x between 0 and 1?
1) x^2 is less than 1
2) x^3 is positive



OA later
1) x^2<1;
x^2-1<0;
(x-1)(x+1)<0;
-1<x<1;
now x can assume both positive and negative values lying between -1 and 1; i.e. x can be either -0.5 or 0.7, as we can't say with surety whether x is lying between 0 and 1 hence 1 alone is not sufficient to answer the question.

2) x^3 is positive; i.e x>0; because now here x can either lie between 0 and 1 or it can be greater than 1 hence 2 alone is not sufficient to answer the question.

combining 1 and 2 we have;
from -1<x<1; and from 2 x>0;
therefore x will lie between 0<x<1;(because here we are looking for a common solution that will satisfy both 1 and 2) hence C
hello bro

statement 1

x^2 is always positive either x is positive or negative but to fulfill the condition that x^2 is less than x then x must be positive and must be between 0 and 1

say x=-0.5 so x^2=0.25 which is greater than x

x=0.5 then x^2=0.25 which is less than x

so statement 1 is sufficient


statement 2

since X^3 is positive, x is positive number but it could be any positive number so insufficient.

oa is A
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by Frankenstein » Wed May 25, 2011 10:42 am
nafiul9090 wrote:
x^2 is always positive either x is positive or negative but to fulfill the condition that x^2 is less than x then x must be positive and must be between 0 and 1

say x=-0.5 so x^2=0.25 which is greater than x

x=0.5 then x^2=0.25 which is less than x

so statement 1 is sufficient


statement 2

since X^3 is positive, x is positive number but it could be any positive number so insufficient.

oa is A
Hi,
In ur question, statement 1 says x^2<1. But in ur explanation u have taken x^2<x. May be typing error in ur question.

Cheers!
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by manpsingh87 » Wed May 25, 2011 10:42 am
nafiul9090 wrote:
hello bro

statement 1

x^2 is always positive either x is positive or negative but to fulfill the condition that x^2 is less than x then x must be positive and must be between 0 and 1

say x=-0.5 so x^2=0.25 which is greater than x

x=0.5 then x^2=0.25 which is less than x

so statement 1 is sufficient
first thing first we have to check whether x lies between 0 and 1 or not i.e. 0<x<1; this is the question..!!!

condition 1 states,,, x^2<1;

now as you said x=-0.5; x^2 will be 0.25 which is less than 1; but x doesn't lie between 0 and 1;
and when we consider x=0.5 ; x^2 will be 0.25, which is less than 1; and x lies between 0 and 1;

so how come 1 alone is sufficient..????

please check your answer again.. logically and mathematically it can't be A...!!!
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by clock60 » Wed May 25, 2011 10:45 am
hi all
in no way the answer is A, it is C
manpsingh87 perfectly worked with this problem, and nothing to add
nafiul9090 can you check the oa again or at least reveal the source
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by nafiul9090 » Wed May 25, 2011 5:18 pm
Frankenstein wrote:
nafiul9090 wrote:
x^2 is always positive either x is positive or negative but to fulfill the condition that x^2 is less than x then x must be positive and must be between 0 and 1

say x=-0.5 so x^2=0.25 which is greater than x

x=0.5 then x^2=0.25 which is less than x

so statement 1 is sufficient


statement 2

since X^3 is positive, x is positive number but it could be any positive number so insufficient.

oa is A
Hi,
In ur question, statement 1 says x^2<1. But in ur explanation u have taken x^2<x. May be typing error in ur question.

Cheers!
hello bro

its my mistake...its typing mistake the correction is

statement 01

x^2 is less than x


source: OG quantitative review 1st ed, DS 73

i apologize for the typing mistake

regards

nafi
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