How do you calculate the final speed when your giving the final time and the starting speed ?

If a car can go from 0.0 to 60.0 mi/hr in 8.0 seconds, what would be its final speed after 5.0 seconds if its starting speed were 50.0 mi/hr ?

We can deduce the car's acceleration using this statement:"a car can go from 0.0 to 60.0 mi/hr in 8.0 seconds".

Then final speed equals acceleration multiplied by time(5s in this case) plus initial velocity(50miles/hour)