(a) The time the ball is in motion is equal to the total time taken to reach its maximum height, plus the time taken to travel the horizontal range, which is given by:
t = (2vi*sin(i))/g + (R)/(vi*cos(i))
(b) The speed of the ball at its peak is given by:
V_peak = √(2g(-R/6))
(c) The initial vertical component of the ball's velocity is equal to vi*sin(i).