solution please written

Earth has a mass of 5.97X1024 kg and orbits the sun with linear velocity 29.8 km/s. The asteroid that is theorised to have caused the KT extinction event had an estimated mass of 1500 billion metric tonnes and was travelling at 20 km/s relative to the sun. If this asteroid struck the earth from directly in front of its direction of travel and was completely incorporated into the earth's crust, what would the % change in earth's velocity be? [Hint, due to the scales involved, you must be careful to avoid losing your answer in rounding errors. Ideally, use algebra and an approximation to avoid this problem entirely.] A 0.42 % B 0.000042 % C 0.000000042 % D 0.042 %