Which ball is moving with the fastest speed?
A) Ball 1
B) Ball 2
C) Ball 3
D) Ball 4

Ball 1 is moving at the fastest speed.. This is because Ball 1, at 100cm distance takes a time of just 10 seconds to cover the distance of 100cm. This is the fastest speed because:

Speed= Distance/Time

Ball 1= 100cm/10= 10 (speed)

Ball 2= 50cm/20= 2 1/2 (speed)

Ball 3= 100cm/20= 5 (speed)

Ball 4= 50/10= 5 (speed)

Therefore Ball 1 has the greatest speed overall.