Let distance between player A and B be x
from,
v = u + at
but,
v = u - gt, for the ball to be acted upon by gravity.
and the negative is to show the direction of g which is down.
u = initial speed(avg speed)
v will be 0m/s since it'll rest after reaching player B.
then,
0= u - (9.8*1.2)
0 =u - 11.76 m/s
u = 11.76 m/s
Therefore, the avg speed is 11.76m/s