Speed

How fast is Usain Bolt? His 100m world record is an amazing 9.58s. Can you work out his average speed for 100m? The Ironman Triathlon provides another interesting real world example of speed. The Ironman involves a 3.86 km swim, a 180.25 km bike ride and a marathon (42.195 km)

Did you know that [|Chrissie Wellington (UK)] hold the women's world record for the Ironman. Here are her split times Can you work out her average speed for each part?
 * Swim 0:50:28
 * Bike 4:40:28
 *  Run 2:57:32