Question

Formulate a pair of linear equations in two variables "$5$ pencils and $7$ pens together cost Rs. $50$, whereas $7$ pencils and $5$ pens together cost Rs. $46$".

Answer 1

Let $x$ and $y$ be the cost of one pencil and one pen

$5$ pencils and $7$ pens together cost Rs. $50$

$\Rightarrow 5x+7y=50$

and $7$ pencils and $5$ pens together cost Rs. $46$

$\Rightarrow 7x+5y=46$