Use one of the equations of motion under constant acceleration:-
s = ut + 1/2 a t^2 where s = displacement, u = initial velocity, a = acceleration due to gravity and t = time .
Here s = 0 , u = 38 m/s and a = -9.8 ms^-2 (negative because its opposed to the motion)
0 = 38t + 1/2 * -9.8 * t^2
-4.9t^2 + 38t = 0
t ( -4.9t + 38) = 0
t = -38 / -4.9 = 7.76 seconds to the nearest hundredth.
