Given that,
Angle θ=450
Velocity v=20m/s
(a).
Now, the time of flight of the projectile over the inclined plane
t=2usinθg
Now, according to question
t=2×20×1√29.8×1√2
t=4.08s
(b).
Now, range OP
R=u2sin2θg
According to question
R=20×20×√2×√29.8
R=81.6m
Hence, the time is 4.08 s and range is 81.6 m