If $2x + y = 5$ and $y - 1 = 0$,then the value of $x$ is ............

$x=-1$ and $y=-2$ is one of the solutions of the equation $\ldots \ldots \ldots \ldots$

By the graphical method,find whether the following pair of equations are consistent or not. If consistent,solve them:
$x+y=3$
$3x+3y=9$

There are some students in the two examination halls $A$ and $B$. To make the number of students equal in each hall,$10$ students are sent from $A$ to $B$. But if $20$ students are sent from $B$ to $A$,the number of students in $A$ becomes double the number of students in $B$. Find the number of students in the two halls.

Solve the following pair of linear equations in two variables using a graph: $y = 2$,$x + 4y = 10$.

The total cost of three tables and two chairs is ₹ $3400$. The cost of two tables and three chairs is ₹ $3100$. Then the total cost of a chair and a table is ₹ ...............