Answer:
speed in meters per seconds = 5x
speed in kilometers per hour = 18
Step-by-step explanation:
The speed is the distance over the time
Given the speed of the stone x meters in 0.2 seconds
So, speed = = = <u>5x meters per seconds</u>
To convert from meters per seconds to kilometers per hour :
1 kilometer = 1000 meters ⇒ 1 meters = 0.001 kilometer
1 hour = 3600 seconds ⇒ 1 second = 1/3600 hour
So, 5x meters per seconds = 5x * 3.6 = <u>18 kilometers per hour</u>