The speed is calculated as distance over time, so:
[tex]\text{speed}=\frac{\text{distance}}{\text{time}}[/tex]Replacing distance by 60 m and time by 3 seconds, we get:
[tex]\text{ speed=}\frac{60\text{ m}}{3\text{ seconds}}=20\text{ m/second}[/tex]The speed of the vehicle is 20 m/second