Momentum = (mass) x (speed) .
So 907,175 kg-m/s = (36,287 kg) x (speed)
Divide each side by (36,287 kg):
Speed = (907,175 kg-m/s) / (36,287 kg)
Speed = 25 m/s
That's the truck's speed. We can't do anything that involves the truck's velocity, because we don't know what direction the truck is moving.