Re: Set $M$ contains numbers that satisfy the condition that, if integer x
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22 Mar 2025, 04:15
OFFICIAL EXPLANATION
We know that set $M$ contains numbers that satisfy the condition that, if integer $x$ is in the set then $x+3$ will also be in the set $M$ in other words we can say that if an elements ' $a$ ' is there in the set all other elements that are multiple of 3 steps away from ' $a$ ' i.e. $a+3 k$, where $k$ is any positive integer, would also be there in the set.
We know that -4 is there in set M ; we need to check that which of the given numbers must also be present in set M.
I. -7 - which might not be there in the set as the set may start with the minimum value of -4 only.
II. -1 - which must be there as $-4+3=-1$
III. 2 - which must be there as $-4+3=-1 \&-1+3=2$ or we can say $-4+2 \times 3=-4+6=2$
Hence only II \& III numbers must be there in the set M, so the answer is (D).