Answer:
20 m/s
Step-by-step explanation:
Your graph is linear, that means it is trying to say that the object moves exact same amount of distance ( 20 m ) in a unit time ( 1 s ).
That means the speed of the object does not change with time.
Y-axis shows the distance the object traveled and X-axis the time taken.
So as your suggest in your equation, try to find the distance the object moved ( 100 m ) in the given time period ( 5 s )
To find a change you should always subtract final value from initial value,
speed = change in distance / change in time
=
=
