Solve the Problem $s = S \sqrt { \frac { x } { L } }$

Solve the problem.
-Police use a formula $s = S \sqrt { \frac { x } { L } }$ , where $S$ is the test-car speed (mph) and $L$ is the test-skid length (feet) , to find the actual speed, s, in an accident which left a skid mark of length $x$ feet. Find the actual speed (to the nearest tenth) when $\mathrm { S } = 63 \mathrm { mph } , \mathrm { x } = 150 \mathrm { ft } , \mathrm { L } = 100 \mathrm { ft }$ .

A) $51.7 \mathrm { mph }$
B) $77.2 \mathrm { mph }$
C) $113.0 \mathrm { mph }$
D) $94.5 \mathrm { mph }$