Answer:
See below
Step-by-step explanation:
45 degree angle will produce the minimal velocity and maximum range...
Maximum range formula= v^2 / g
90 000 m = v^2 / 9.81 m/s^2
v = 939.6 m/s
Time would be calculated by using the horizontal component and the horizontal speed
90 000m / ( 939.6 m/s cos 45 m/s ) = 135.5 s