You can calculate it from the formula for velocity
v=[tex] \frac{s}{t} [/tex]
if it travels 450 yards in 15 seconds
s=450 yards t= 15s
1 yard = 3 feet so
s= 1350 feet
v=[tex] \frac{1350}{15}=90 \frac{feet}{s} [/tex]
so if in one second it travels 90 feet, in [tex] \frac{1}{3} [/tex] of a second it travels [tex] \frac{90}{3} =30[/tex] feet
