Question

What will be the answer??

Answer 1

5-a).  Acceleration is a vector defined as the rate of change of velocity.
Its magnitude has units of [length/time²].  The SI unit is meter/second².
Its direction is the direction in which velocity is increasing. 

5-b).  The graph says that the object's speed is not changing.
When we look at any time, from zero to almost 50 minutes, the
object's speed is the same . . . 60 m/s .  This will make it easy.

There are 60 seconds in a minute, so 30 minutes = 1,800 seconds.
In every one of those seconds, the object covered 60 meters.
It travelled a total of (60 m/s)·(1,800 s) = 108,000 meters (108 km) .