Im stuck on this practice question and how to get the answer, what is a universal set?-
Suppose U={3,4,5,6,8,11,12,14,15} is a universal set and A={4,5,8,12,15}. What is A?
A:{3,4,6,8,11,14}
B:{3,6,11,14}
C:{4,6,8,15}
D:{3,6,11,12,14}

Question

Im stuck on this practice question and how to get the answer, what is a universal set?-
Suppose U={3,4,5,6,8,11,12,14,15} is a universal set and A={4,5,8,12,15}. What is A?
A:{3,4,6,8,11,14}
B:{3,6,11,14}
C:{4,6,8,15}
D:{3,6,11,12,14}

reemii · Answer

Don't you mean:  What is $A^c$? (or $\bar A$ or $A^\star$ depending on the notation you use for the "complementary set")?

fo14 · Answer

no the question just said A

reemii · Answer

The universal set $U$ will contain all possible results of an experience (made by somebody somewhere).
The set $A$ are some results that of interest. The complementary (what is in $U$ but not in $A$) set of $A$ is $U\setminus A = \{3,6,11,14\}$.

reemii · Answer

it doesn't make sense to say "what is A" without proposing A that was defined just before. There must be a missing word there.