Please solve this problem

when the angle between the velocity vector and the horizontal component is 30^. . the vertical component is given by,
u sin 30 = 20  x (3)^1/2  x 1/2 = 10 x 1.73 = 17.3 m/s.
vertical component  at the start of the motion = 20 x root 3 x root 3 x 1/2 = 30 m/s.
now taking , v = 17.3 m/s , u = 30 m/s and , g = -10m/s²
v = u + gt  . therefore , t = 12.7/10 = 1.27 s. 
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