Jack swims a distance of 9*25.0m=225.0 meters is 2 min and 34.5 seconds.
2 min and 34.5 seconds are 2*60sec +34.5 sec= 154.5 s
Jill covers 10*25.0m = 250 m in 154.5 s.


thus,
the speed of Jack is : 225.0 meters /154.5 s =(225/154.5) m/s = 1.46 m/s
the speed of Jill is : 250.0 meters /154.5 s =(250/154.5) m/s = 1.62 m/s
Assuming Jack and Jill depart from point 0 towards the positive direction,
each even number of lengths, means Displacement = 0, and each odd number of lengths means Displacement = 25 m
So, average Velocity of Jill is 0,
average velocity of Jack is 25/ 154.5 = 0.16 m/s
Answer:
Average Speed of Jack : 1.46 m/s
Average Speed of Jill : 1.62 m/s
Average Velocity of Jack : 0
Average Velocity of Jill : 0.16 m/s