If $A = \{x, y\}$,then the power set of $A$ is

In a city $20$ percent of the population travels by car,$50$ percent travels by bus and $10$ percent travels by both car and bus. Then the percentage of persons travelling by car or bus is......$\%$.

If $A$ and $B$ are two sets,then $A \cap (A \cup B)'$ is equal to

If $A$ and $B$ are any two non-empty sets and $A$ is a proper subset of $B$. If $n(A) = 4$,then the minimum possible value of $n(A \Delta B)$ is (where $\Delta$ denotes the symmetric difference of set $A$ and set $B$).

Which of the following sets is finite?

Let $A = \{(x, y) : y = e^x, x \in R\}$ and $B = \{(x, y) : y = e^{-x}, x \in R\}$. Then: