well, the idea being, that 1 is the 100% unit, so say 0.5 is 50% and so on.
so, let's convert 7 and 7/8 from mixed to improper first.
[tex]\bf 7\frac{7}{8}\implies \cfrac{7\cdot 8+7}{8}\implies \cfrac{63}{8}\implies 7.875\\\\
-------------------------------\\\\
\begin{array}{ccll}
amount&\%\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
1&100\\
7.875&p
\end{array}\implies \cfrac{1}{7.875}=\cfrac{100}{p}\implies p=\cfrac{7.875\cdot 100}{1}[/tex]
