How many kilometers can a speed of 400 yards cover in one hour?

[LeHenry]

400 yards per hour can cover 640 kilometers. 40 yards: refers to a speed of 40 miles per hour; 1 mile = 1.609 kilometers; 40 yards = 64 kilometers per hour. Origin: A speed of 40 yards equals 64 kilometers per hour. The common expression of speed in 'yards' originates from the speed unit 'mile'. One mile equals 1 mile per hour, which converts to approximately 1.6 kilometers per hour in the metric system. Common Metric System: Internationally, the common metric system is used, where a speed of 100 yards is equivalent to 100 kilometers per hour. The British expression of 100 miles equals 160 kilometers per hour. In reality, 'mile' refers to 'Mile', where 1 mile = 1.6 kilometers. Therefore, precisely speaking, 40 miles equals 64 kilometers per hour.