The distance-time graph below represents the motion of two buses $A$ and $B$.
$(i)$ What is the distance by which bus $B$ was ahead of bus $A$ initially?
$(ii)$ Do they ever meet each other? If so,when?
$(iii)$ What is the distance travelled by bus $A$ when it overtakes bus $B$?
$(iv)$ Find out the distance by which bus $A$ was ahead of bus $B$ at $t = 12 \ h$.
$(v)$ Which one of them is moving faster? Give reason.

(N/A) $(i)$ At $t = 0 \ h$,bus $B$ is at $20 \ km$ and bus $A$ is at $0 \ km$. Thus,bus $B$ was ahead by $20 \ km$.
$(ii)$ Yes,they meet at the point where the two lines intersect,which is at $t = 9 \ h$.
$(iii)$ At the point of intersection $(t = 9 \ h)$,the distance on the $y$-axis is $60 \ km$. Thus,bus $A$ has travelled $60 \ km$.
$(iv)$ At $t = 12 \ h$,bus $A$ is at $80 \ km$ and bus $B$ is at $70 \ km$. The difference is $80 \ km - 70 \ km = 10 \ km$.
$(v)$ Bus $A$ is moving faster because the slope of its distance-time graph is steeper than that of bus $B$,indicating a higher speed.