Question

If a varies inversely as square root of $b$ and $a=7$ when $b=36$, find $a$ when $b=289$

• A. $42$
• B. $17/42$
• C. $42/17$
• D. None of these

Answer 1

The correct option is C $42/17$

Given, $a=7,b=36$

We need to find $a$ when $b=289$.

$y=\frac{k}{x}$ $\Rightarrow a=\frac{k}{\sqrt{b}}$
$\Rightarrow 7=\frac{k}{\sqrt{36}}$
$\Rightarrow 7=\frac{k}{6}$ $=$ $k=42$ ,
Therefore, $a=\frac{42}{\sqrt{b}}$
$\Rightarrow a=\frac{42}{\sqrt{289}}$
$\Rightarrow a=\frac{42}{17}$