Question

Question 27

If x varies directly as y, then
$\begin{array}{ccc}x& 12& 6\\ y& 48& -\end{array}$

Answer 1

If x varies directly as y, then
$\frac{x}{y}=k\left(cosstant\right)....\left(i\right)$
If x =12 and y =48, then
If x =12 and y =48, then
$\frac{x}{y}=\frac{12}{48}=\frac{1}{4}\Rightarrow k=\frac{1}{4}$
When x =6, then from Eq.(i)
$\frac{6}{y}=k$
$\Rightarrow \frac{6}{y}=\frac{1}{4}$ [putting the value of k]
$\Rightarrow 6\times 4=y\times 1$ [by cross-muliplication]
$\Rightarrow y=24$