500 DS tricky

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500 DS tricky

by dunkin77 » Mon Apr 02, 2007 2:30 pm
Hi,

I thought the answer is E) but the correct answer is B).

i) says if there is 2, there should be -2 in S; however, ii) says a and b (differrent number) can be multiplied "ab" but it dose not say same number a and -a can be multiplied..... I am confused.. :cry:

. S is a set of integers such that
i) if a is in S, then –a is in S, and
ii) if each of a and b is in S, then ab is in S.
Is –4 in S?
(1) 1 is in S.
(2) 2 is in S.

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Re: 500 DS tricky

by ajith » Mon Apr 02, 2007 5:39 pm
dunkin77 wrote:Hi,
ii) says a and b (differrent number) can be multiplied "ab" but it dose not say same number a and -a can be multiplied..... I am confused.. :cry:
who said a and -a are not different numbers ???
It is quite different.

If it were same, could you please lend as much as you can, and later on I will say lending and borrowing are the same.
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by dunkin77 » Mon Apr 02, 2007 7:33 pm
Okie - a and -a is different number then! :wink: