clar wrote:the ans according to me should be A but it is given to be C
Can someone explain how?
my reasoning says that
if 3 is in P and x+3 is also in P , then all positive multiples of 3 will be in P.
this is because for both the above conditions to be valid , the value of x should be 0.
where am i faltering?
you are right
A should be the answer.
because if 3 is there in the set then all the multiples must be there
a) SUFF
b)NOT SUFF, because it will depend upon what the set is
it can be {...-6,-3,0,3}
or it can be the infinite set {...-6,-3,0,3,6.....}
NOT SUFF
The powers of two are bloody impolite!!