If $A = \{x : x = \frac{n-1}{n+1}, n \in W\}$ and $\{n \leq 10\}$,point out the correct statement from the following:

If $aN = \{ ax : x \in N \}$,then the set $3N \cap 7N$ is equal to .....$N$.

There are $80$ families in a small extension area. $20$ percent of these families own a car each. $50$ percent of the remaining families own a motor cycle each. How many families in that extension do not own any vehicle?

If $A = \{a, d\}, B = \{b, c, e\}$ and $C = \{b, c, f\},$ then $A \times (B \cap C) =$

In a group of $1000$ people,there are $750$ people who can speak Hindi and $400$ who can speak English. How many can speak Hindi only?

Write down the power set of the set ${0}.$