Final answer:
Sally was running at a speed of 0.5 meters per second.
Step-by-step explanation:
To calculate the speed at which Sally was running, we can use the equation:
Speed = Distance / Time
Given that Sally ran 10 meters in 20 seconds, we can substitute these values into the equation:
Speed = 10 meters / 20 seconds
Speed = 0.5 meters per second
Therefore, Sally was running at a speed of 0.5 meters per second.