Answer:
9 Km/h
Step-by-step explanation:
Walking 3 Km for 20 minutes from the definition of speed, it's distance covered per unit time. Here, the distance covered is expressed per unit hour.
[tex]Speed=\frac {distance}{time}[/tex]
Substituting 3.5 Km for distance and time for 20 minutes
To convert time into hours, we divide the minutes by 60 hence time=20/60=1/3 hours
[tex]Speed=\frac {3 Km}{1/3 hours}=9 Km/h[/tex]
Therefore, the speed is 9 Km/h