Since we are ignoring air resistance than the initial speed v would be the same as initial speed v at max height because the horizontal component's velocity doesn't change. The speed at launch would also be speed V.
I'm not sure if this is correct but I used Savg=TotalDistance/Δt
Total Distance = 250m/s(3.03s) = 758m rounded up.
The answer does match the one in the book.
45=0*t+.5(9.8)t^2
(45/4.9)^(1/2) = 3.03s
Thank you so much for your help LawrenceC!
So if I was asked At what horizontal distance from the firing point does it strike the ground? I would use a similar eqn to solve it while plugging in t correct?