Falling object: time before it reaches the ground and its position

[ellyb]

A flowerpot is knocked off a balcony 20.0m above the sidewalk and falls toward an unsuspecting 1.75-m tall man who is standing below. How close to the sidewalk can the flowerpot fall before it is too lat for a warning shouted from the balcony to reach the man in time? Assume the man below requires 0.300s to respond to the warning.
d=1/2gt2
18.25m=4.9t2
1.93s=t for flowerpot to fall
v=d/t
v=343m/s at 20C
343=18.25/t
t=.053s for sound to reach man
So, tflower=tlast instant+tsound+treaction
1.93=.053+.3+t
1.577s=t
okay, d=1/2gt2
d=4.9(1.5772)
12.2m=dCan someone help me i am not sure if i did it right?

 

[Pheo1986]

that seems gd to me. it has fallen 12.2m so it will be 7.8m above the sidewalk