In Poland, we use the metric system, i.e. we use meters, centimeters and kilometers to specify distances. For example, the US is dominated by the use of miles. Hence the question of how many kilometers is one mile, and how do you convert this into kilometers?
One mile is exactly 1,609,344 meters, or 1,609344 kilometers. However, to make the conversion more convenient, we can round this value to 1.6 km.
So, for example, a speed of 100 miles per hour corresponds to 160 km / h.