Question

In which of the following tables $x$ and $y$ vary inversely:​

$\begin{array}{ccccc}x& 5& 20& 10& 4\\ y& 20& 5& 10& 25\end{array}$

Answer 1

Step : Check if $x$ and $y$ vary inversely

We know that,
If $x$ and $y$ vary inversely, then the product $xy$
remains same for all values of $x$ and $y$

$\begin{array}{ccccc}x& 5& 20& 10& 4\\ y& 20& 5& 10& 25\end{array}$

From the given table, we have
$x\times y=5\times 20=20\times 5=10\times 10=4\times 25=100$

Clearly, the products of the values of $x$ and the
corresponding values of $y$ are fixed and is equal to $100$.

Hence, $x$ and $y$ vary inversely with each other.