. If $A, B$ are any two sets, then $A\cap (B-A)=$

 If $A, B$ and $C$ are any three sets, then$A-(B\cap C)$

If $U=(1, 2, 3,....10)$ is the universal set, $A = (1, 2, 5)$ and $B=(6, 7)$. Then $A\cap B\text{'}$ = 

If $A= \varnothing$, then $A =$

If $A (a, b, c), B = (a, b), C (a, b, d), D= (c, d)$ and $E = \left(d\right)$, an incorrect statement is

In a committee, $20$ people speak English, $30$ speak Hindi and $10$ speak both English and Hindi. The number of people who speak at least one of these two languages is