What is the speed in km/min of a skater who travels a distance of 210 m in a time of 30 seconds

Answer: 0.42 km/min

Explanation:

total distance traveled (in meters) = 210m

total distance traveled (in km) = 210 : 1000 = 0.21 km

total time taken (in seconds) = 30 s

total time taken (in minutes) = 30 : 60 = 0.5 s

speed = (distance traveled) : (time taken) [in km/min] = 0.21 : 0.5 = 0.42km/min