Is n < 1 ?
(1) nx – n < 0
(2) x–1 = –2
OA: C
Please explain, thank
Source: Manhattan challenge problem
manhattan challenge problem_DS_is n < 1
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I am getting E
Stmt I
nx-n<0
n(x-1)<0
n->positive greater than 1 and x-1<0 then NO n is not less than 1
n-> negative and x-1>0 then YES n<1
INSUFF
Stmt II
x-1 = -2
No idea what n could be
TOGETHER:
n (x-1) < 0
x-1 = -2
-2n < 0
All we can say is n>0
n = 10000000 NO
n=1/2 YES
Must be missing a trick if its C
Regards,
CR
Stmt I
nx-n<0
n(x-1)<0
n->positive greater than 1 and x-1<0 then NO n is not less than 1
n-> negative and x-1>0 then YES n<1
INSUFF
Stmt II
x-1 = -2
No idea what n could be
TOGETHER:
n (x-1) < 0
x-1 = -2
-2n < 0
All we can say is n>0
n = 10000000 NO
n=1/2 YES
Must be missing a trick if its C
Regards,
CR
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Just my opinion..
I think the above problem makes more sense if
a) = nx - x instead of nx - n
if it is nx - x then the answer is definitely C..
Can you confirm the above please?
I think the above problem makes more sense if
a) = nx - x instead of nx - n
if it is nx - x then the answer is definitely C..
Can you confirm the above please?
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IMO E for me too.
To find out if n<1 we have to find out the value of n?
From A we cannot say that n is positive or negative..becoz we
don't know the value of x.(insufficient)
From B we get the value of x that is -1.(insufficient)
Now when we take them together and put the value of
x in nx-n< 0
= -n-n < 0
=-2n<0
now if we take n as negative that is say -1 we get n> 0.
and if we take n as postive say 1 we get n < 0.
To find out if n<1 we have to find out the value of n?
From A we cannot say that n is positive or negative..becoz we
don't know the value of x.(insufficient)
From B we get the value of x that is -1.(insufficient)
Now when we take them together and put the value of
x in nx-n< 0
= -n-n < 0
=-2n<0
now if we take n as negative that is say -1 we get n> 0.
and if we take n as postive say 1 we get n < 0.
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From statement (2) ==>x = – 1 , but no info abt n ==> insufficient
From statement (1) ==> n (x – 1 ) < 0 . If n = – 1 and x =2 , n (x – 1 ) < 0 but when n = 2 and x = 0 , then n (x – 1 ) < 0 ==> insufficient
Both statements together ==>if x = – 1, and n (x – 1 ) < 0 ==> n > 0 ==>sufficient
Why? when the red portion is negative, the blue portion MUST be positive; otherwise, the inequaility( <0 )does not hold
From statement (1) ==> n (x – 1 ) < 0 . If n = – 1 and x =2 , n (x – 1 ) < 0 but when n = 2 and x = 0 , then n (x – 1 ) < 0 ==> insufficient
Both statements together ==>if x = – 1, and n (x – 1 ) < 0 ==> n > 0 ==>sufficient
Why? when the red portion is negative, the blue portion MUST be positive; otherwise, the inequaility( <0 )does not hold