Answer
We have 3 stages of motion of this object:
1- From $t=0\;\rm s$ to $t=200\;\rm s$, the object moves at a constant speed (since the slope is constant). During this stage, it travels 100 m.
2- From $t=200\;\rm s$ to $t=400\;\rm s$, the object stops
During this stage, it covers no distance at all.
3- From $t=400\;\rm s$ to $t=600\;\rm s$, the object moves at a constant speed again and in the same direction as well. During this stage, it travels 200 m.
Work Step by Step
We have 3 stages of motion of this object:
1- From $t=0\;\rm s$ to $t=200\;\rm s$, the object moves at a constant speed (since the slope is constant). During this stage, it travels 100 m.
2- From $t=200\;\rm s$ to $t=400\;\rm s$, the object stops
During this stage, it covers no distance at all.
3- From $t=400\;\rm s$ to $t=600\;\rm s$, the object moves at a constant speed again and in the same direction as well. During this stage, it travels 200 m.
You can replace the word object with any real thing like a cat.