What must your speed be in order to travel 400 km in 3 hrs? Physics · College · Wed Jan 13 2021 llm Answered on Fri Oct 28 2022 Formula : Speed = Distance/timeDistance = 400 kmTime = 3 hoursSpeed = 400/3 km/hr= 133.33 km/hr Hence, speed must be 133.33 km/hr to travel 400km in 3 hours.