Re: A set of numbers has the property that for any number t in the set, t
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19 Nov 2022, 04:16
The constraint suggests that if 't' is present then 't+2' must be present.
Now coming to the question,
1. if - 1 is present then - 1 + 2 = 1 must be present.
2. If 1 is present then 1 + 2 = 3 must be present and so on
So the set must have - 1, 1, 3, 5, ... so on.
One may think that since - 1 is there so - 3 must be there. But that is not what the constraint states. The mere presence of -1 does not mean - 3 will be there.
So other I, the other two (II, III) must be true. 'I' can be true but NOT must.
The answer is D.