How do i solve this physics problem?

Question

a car is moving at 40m/h. it finished it's 200 track after just 3 hrs. if it accelerated during the 2nd hour, what is it's acceleration and speed during the last hours?

Answer 1

using two of the kinematic equations

x = Vo(t) + 1/2 (a)(t^2)

and

Vf = Vo + a(t)

where Vf = Final Velocity

Vo = Initial velocity

t = time in hours

a = unknown in m/h

x = distance traveled

based on the information given, we know that initial velocity is 40m/h, and there was no acceleration during the first 2 hours, so using  x = Vo(t) + 1/2 (a)(t^2)

x = 40(2) + 1/2 (0) (2^2)

x = 80m

so in the last hour, the car must travel 120 meters, using

x = Vo(t) + 1/2 (a)(t^2) again

120 = 40(1) + 1/2(a)(1^2)

we find that a = 160m/h

then using Vf = Vo + a(t) , we can find final velocity too

Vf = 40 + 160(1)

Vf = 200m/h

thats a very slow moving car