Choose the correct solution in roster form: Suppose X = {1, 2, 3, 4, 5, 6 } is the universal set and P =

Question

{2, 4, 6}. What is P’?
a. {1,3}
b. {1,5}
c. {1,3,5}
d. {3,5}
I don't need you to tell me the answer but could you please tell me what the universal set means? so I can solve it on my own.
Thank you and have a great day. :)

Answer 1

In any particular question dealing with sets, the universal set is the
set within all dealings, discussion and/or calculations take place. You don't
consider any other elements except those of the universal set.

e.g. if your universal set is the set of integers, then addition, subtraction and
multiplication of any two elements will yield an element within that universal set.
However division between two elements of the universal set may yield results that are not in the universal set.
e.g. 5 and 3 are both elements of I, but 3/5 is not found in I (the integers)

so in your question we can only talk about the elements of {1, 2, 3, 4, 5, 6}
clearly P, which is {2,4,6} is a subset of X, since all the elements of P are found in X.
The notation P' means "not P", so it would be all those elements of X not stated in P
P' = {1, 3, 5}

Answer 2

Thank you so much I now understand this question so much better.