a car initially traveling at 60 km/h accelerates at a constant rate of 2.0 m/s ^2. how much time is required for the Car to reach a speed of 90km/h

First put km/h into m/s. We get the car is traveling at 16.67m/s and that he need to get up to 25m/s (90km/h). Now since we know what vf, vi, and a are, we can plug this into vf = vi + at and using algebra get t= 25-16.67/2, so t= 4.165s