[tex]y=yo+vo*t- \frac{g*t^2}{2} [/tex]
yo=0
y=120 cm =1,2m
[tex]v_f^2 =v_o^2-2g*y [/tex]
[tex]v_o= \sqrt{2g*y} = \sqrt{2*9,8*1,2} = 4,849m/s[/tex]
[tex]v_f=v_o -gt [/tex]
[tex]t = \frac{v_o}{g} =0,49s[/tex]
t is the time to get just the maximum height.
so the total time he spent in air is Ttotal=2*t
Ttotal= 0,98s
