If the sum and the difference of the digit at the ten's place and the digit at the unit's place of a two-digit number are the same,then the digit at the unit's place is ...........

$A$ shopkeeper sells a saree at $8 \%$ profit and a sweater at $10 \%$ discount,thereby,getting a sum of $Rs. 1008$. If she had sold the saree at $10 \%$ profit and the sweater at $8 \%$ discount,she would have got $Rs. 1028$. Find the cost price of the saree and the list price (price before discount) of the sweater (in $Rs.$).

The solution set of the pair of equations $x+y+1=0$ and $3x+3y+k=0$ is an infinite set. Then $k = \dots$

Five years ago,the sum of the ages of five persons was $50$ years. After five years,the sum of the ages of those five persons will be $\ldots \ldots \ldots \ldots$ years.

The pair of equations $ax - y = 5$ and $4x - 2y = 10$ has an infinite number of solutions. Then $a = \ldots$

Obtain a pair of linear equations in two variables from the following information: Three years ago,the age of Abhishek was four times the age of Sweta. After five years,the age of Abhishek will be two times the age of Sweta.