The math is correct, but I wonder about the real world. I don't know much about competitive biking, but you've got this dude pumping along at almost 25 mph for 40 minutes solid. Is this realistic ?
Distance for which the bike is ridden = 30 km Speed at which the bike is driven = 0.75 km/minute Let us assume the number of minutes taken to travel the distance of 30 km = x Now we already know the formula of speed can be written as Speed = Distance traveled/ Time taken 0.75 = 30/x 0.75x = 30 x = 30/0.75 = 40 minutes So the time taken for riding a distance of 30 km will be 40 minutes. I hope this procedure is simple enough for you to understand.