velocity-time curve problem

A train start to move from rest and then travel its first part with constant acceleration of then travel the second part of the constant velocity of V then travel the third part of the constant **deceleration** of then it comes to rest.So draw a velocity - time curve and it travel constant velocity with the of the total time and the average speed of the total travelling is **KV.so find out the value of k? so please give me the ideas to do that.**

Re: velocity-time curve problem

Re: velocity-time curve problem

I am really sorry i assume the total time for travelling is t.when it travel in the constant velocity of V with 3/4t of the total time (sorry for mention 4/3)