sets

[naaga]

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.


help anyone with explanation..

thanks in advance

[cramya]

I would go wiht B

Stmt I

1 is in S. Therefore by i) -1 is in S and by ii) agian 1*-1 i.e -1 is in S

No ways to predict if -4 is in S or not

INSUFF

Stmt II

2 is in S

By i) -2 is in S and by ii) 2 * -2 = -4 is in S

SUFF

[naaga]

ok ok I got it

here a and b means ( a * -a) write ?

thankyou cramya..

[cramya]

No problem, Naga! Wish u the very best in your prep.

Regards,
CR

[peddisetty]

We can clearly tell -4 is not in the set. So the first choice is sufficient.

So the Answer would be D. Please clarify cramya.

Thanks,
Raj.