Is n negative?
i)n5(1 - n4) < 0
ii) n4 - 1 < 0
(n5 refers to n to the power 5 and n4 above refers to n to the power 4)
Inequality DS
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I would go with C
Stmt I
n^5*(1-n^4) < 0
Either n^5<0 which would make n negative
or
1-n^4 < 0 n can be positive or negative
INSUFF
Stmt II
n^4 < 1
n=-1/2 n =1/2
INSUFF
Together
WE know n^4<1 so 1-n^4 is positive
Since n^5(1-n^4)<0 therefore n^5 neagtive and hence n is negative
Choose C
Stmt I
n^5*(1-n^4) < 0
Either n^5<0 which would make n negative
or
1-n^4 < 0 n can be positive or negative
INSUFF
Stmt II
n^4 < 1
n=-1/2 n =1/2
INSUFF
Together
WE know n^4<1 so 1-n^4 is positive
Since n^5(1-n^4)<0 therefore n^5 neagtive and hence n is negative
Choose C
Hi Cramya,
I agree with your ans i.e C.
But what if I approach the question as below:-
n^5(1-n^4) < 0
(n^5 - n^9) < 0
n^5 < n^9
Now if n is positive, n^5 < n^9 is always true.
Now if n is negative, n^5 > n^9 will always be true.
So is A not sufficient as one can deduce that n is always gretare then n.
I know I am missing some point somewhere.Please point out the same.
I agree with your ans i.e C.
But what if I approach the question as below:-
n^5(1-n^4) < 0
(n^5 - n^9) < 0
n^5 < n^9
Now if n is positive, n^5 < n^9 is always true.
Now if n is negative, n^5 > n^9 will always be true.
So is A not sufficient as one can deduce that n is always gretare then n.
I know I am missing some point somewhere.Please point out the same.
- codesnooker
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No the above statement will be always true only when n>1. If n lies between 0 and 1, i.e.rahul26 wrote: Now if n is positive, n^5 < n^9 is always true.
0 < n < 1, then
n^5 > n^9
Same case with your second statement.
Hence statement 1 is not alone sufficient.