initial velocity, final velocity or average velocity???

Initial velocity always refers to the velocity of an object at the start of a certain action. e.g. a ball is thrown at 4 km/hr ; an object starts from 10 km/hr, a boy jumps at 5 km/hr into the river, a bullet was shot at a velocity of 30 m/s, a coin was dropped at a velocity of 5 m/s etc. These all mean initial velocity.

When you are asked how fast a certain object goes after a certain time, it refers to the velocity at the end of that specified time. e.g. what is the velocity of the ball after 10 seconds, what is the velocity of the train at 5 pm if it starts at 1 pm
When a question asked about average velocity, the word - average - will appear in the question. e.g. a train takes 3 hours to travel 90 km, what is the average velocity of the train ?

a boy walks 10 km after 2hours, what is his average velocity?

1
40m/s a initial velocity , because you throw up at a initial speed 40m/s .The velocity of an object after 6s is a Instantaneous velocity.
2
it also ask the Instantaneous velocity. since it ask how fast will it be traveled after 5s, it is the value at 5s, not the average velocity between 0-5s