A ball is thrown toward a cliff of height h with a speed of 28m/s and an angle of 60∘ above horizontal. It lands on the edge of the cliff 3.3s later.

a) How high is the cliff? i got 26.7 m
b) What was the maximum height of the ball? my answer here was 30 m
C) What is the ball's impact speed?
I found fall time 3.3-2.47=0.83s
then I used this formula V1=V0+gt = 0+9.80*0.83 = 8.13m/s
But my answer is wrong. where am I wrong?
Thanks