Question

If t varies directly with s and inversely with the square of r, and s = 48 when t = 8 and r = 3. Find s

when t = 12 and r = 5.

Answer 1

`\qquad \qquad \textit{combined proportional variation} \\\\ \begin{array}{llll} \textit{\underline{y} varies directly with \underline{x}}\\ \textit{and inversely with }\underline{z^5} \end{array} ~\hspace{6em} \stackrel{\textit{constant of variation}}{y=\cfrac{\stackrel{\downarrow }{k}x}{z^5}~\hfill } \\\\[-0.35em] ~\dotfill`

`\begin{array}{llll} \textit{`