Answer
$\beta = 0.480$
Work Step by Step
We can find the velocity:
$v = \frac{\Delta x}{\Delta t}$
$v = \frac{480~m-1200~m}{5.00\times 10^{-6}~s}$
$v = -1.44\times 10^8~m/s$
We can find the speed parameter:
$\beta = \frac{\vert v \vert}{c} = \frac{1.44\times 10^8~m/s}{3.0\times 10^8~m/s} = 0.480$
