\begin{equation*}
(n+1)s = 7 \cdot 0.42 = 2.94
\end{equation*}
and so m = 2 and r = 0.94. Thus, the percentile will lie between \(y_2 = 47\) and \(y_3 = 54\) and much closer to 54 than 47. Numerically
\begin{equation*}
P^{0.42} = 0.06 \cdot 47 + 0.94 \cdot 54 = 53.58.
\end{equation*}