Question

If y varies inversely with x, and y= 2 when x= 8, what is k, the constant of proportionality?

Answer 1

`\bf \qquad \qquad \textit{direct proportional variation} \\\\ \textit{\underline{y} varies directly with \underline{x}}\qquad \qquad y=kx\impliedby \begin{array}{llll} k=constant\ of\\ \qquad variation \end{array}\\\\ -------------------------------\\\\ \textit{we also know that } \begin{cases} y=2\\ x=8 \end{cases}\implies 2=k8\implies \cfrac{2}{8}=k\implies \cfrac{1}{4}=k`