Question

If j and k are inversely proportional and j = 16 when k = 21, what is the value of j when k = 14?

Answer 1

`\bf \qquad \qquad \textit{inverse proportional variation} \\\\ \textit{\underline{y} varies inversely with \underline{x}}\qquad \qquad y=\cfrac{c}{x}\impliedby \begin{array}{llll} c=constant\ of\\ \qquad variation \end{array}\\\\ -------------------------------`


`\bf \stackrel{\textit{\underline{j} and \underline{k} are inversely proportional}}{j=\cfrac{c}{k}}\qquad \textit{we also know that } \begin{cases} j=16\\ k=21 \end{cases} \\\\\\ 16=\cfrac{c}{21}\implies 336=c\qquad therefore\qquad\qquad \boxed{j=\cfrac{336}{k}} \\\\\\ \textit{when k = 14, what is \underline{j}?}\qquad j=\cfrac{336}{14}`