4. An automobile is traveling at 30 km/hr. It accelerates at 3 m/s2 until it has covered 100 meters.. What is its new velocity?

I asked my teacher on what formula I should use and said I should use this one: V^2= Vo^2+2ax (V^2 is the velocit, Vo is the initial velocity, a is accerlation and x distance

I used that formuala and got 668.90 m/s

V^2= (8.3 m/s)^2+2(3m/s^2)(100 m)=668.90 m/s

I converted 30km/hr by doing this:
(30 km/hr)(1000 m/km)(1hr/3600)=8.3m/s

Now I understand how to get 25.9 m/s, but now how to I convert it to 93.2 km/hr?

Just the reverse of the way you converted 30 km/hr to m/s.

25.9 m/s(3600 s/hr)(1 km/1000m) = ??