Physics help !!!?

Question

By how much does a speed of a vehicle moving in a straight line change when it is accelerating at 6km/h-s ?

Answer 1

V=at
V- velocity
a- constant acceleration
t - time

and 6km/h-s is not an acceleration
acceleration is in say km/h^2 (length per time squared)
unless you meant to say
6 km/ hour for every second
then
a= 6000/ 3600 s 1s
a= 1.67m/s^2

Answer 2

To answer this you need to know for how long the acceleration is applied and in what direction. Even braking is an acceleration.