Solve the following pairs of equations by the cross-multiplication method:
$0.5x + 0.3y = 0.1$
$0.6x + 0.3y = 0.3$

Are the following pair of linear equations consistent? Justify your answer.
$2ax + by = a$
$4ax + 2by - 2a = 0$; $a, b \neq 0$

$A$ two-digit number is such that the product of its digits is $10$. When $27$ is added to the original number,the new number obtained is the same as the number obtained by interchanging the digits of the original number. Determine the number.

Places $A$ and $B$ are $90\, km$ apart from each other on a highway. $A$ car starts from $A$ and another from $B$ at the same time. If they move in the same direction,they meet in $9$ hours and if they move in opposite directions,they meet in $\frac{9}{7}$ hours. Find the speeds of the cars.

If $(1, y)$ is the solution of the linear equation of two variables $2x + 3y = 8$,then $y = \ldots$

An employee invests ₹ $x$ at the rate of $5 \%$ and invests ₹ $y$ at the rate of $7 \%$,then he gets ₹ $310$ as yearly interest. Symbolically it is written as ..........