[tex]\stackrel{mixed}{7\frac{1}{4}}\implies \cfrac{7\cdot 4+1}{4}\implies \stackrel{improper}{\cfrac{29}{4}} \\\\[-0.35em] ~\dotfill\\\\ \begin{array}{ccll} K ms&hours\\ \cline{1-2} 681 & 1\\ x& \frac{29}{4} \end{array} \implies \cfrac{681}{x}=\cfrac{1}{~~ \frac{29}{4}~~}\implies \cfrac{684}{x}=\cfrac{4}{29} \\\\\\ 19836=4x\implies \cfrac{19836}{4}=x\implies 4959=x[/tex]
