He has to travel 78 000 000km, and he is going 20 km/s, so its 78 000 000/20 = 3 900 000 seconds , then you take that and transfer it to minutes by dividing by 60 , 3 900 000 / 60 = 65 000 minutes then to hours , 65 000 / 60 = 1083 hours , then days 1083 / 24 = 45 days