A rocket has been fired at a 45-degree angle for 3.5 seconds. The rocket travelled in a straight line at a speed of 125m/second.
v0 = launch speed
θ = launch angle above horizontal
t = time [In the problem you give two times, 1 min and 3.5 sec. I will solve it for 3.5 sec, you do do the other.]
x(t) = horizontal distance traveled in time t
Neglecting air resistance,
x(t) = (v0cosθ)t = (125 m/s)(cos45°)(3.5 s) ≅ 309 m
Plug in t = 60 sec for the other case.