Bunuel wrote:
(2) The product of any two of the numbers A, B, C and D is between 0 and 1. So, we have that the product of ANY two of the numbers is positive. This implies either that all the numbers are negative or that all the numbers are positive. In the first case the answer is NO and in the second case the answer is YES. Not sufficient.
Hi Bunuel,
I have been reading your posts quite regularly, and they are very helpful. I am really grateful to you for providing assistance to people like us.
As far as this question is concerned i have a doubt on s(2). As you have mentioned above "that all the numbers are negative or that all the numbers are positive."
I have been working on one or two examples and came across this one
Suppose B and C are -1/2 and -1/3. Their product is 1/6, which is between 0 and 1. Now the possible values can be
A<B<C<D :- -1 < -1/2 < -1/3 <1 . In this case |A| + |B| IS NOT LESS THAN |C| + |D| insufficient
Suppose A and B are -1/2 and -1/3. Again their product is 1/6, which is between 0 and 1. Now the possible values can be
A<B<C<D :- -1/2 < -1/3 < 1 < 2. In this case |A| + |B| < |C| + |D| sufficient.
So, how can we say "that all the numbers are negative or that all the numbers are positive." ? and it doesn't say that The product of
every two of the numbers A, B, C and D is between 0 and 1.
Thanks