There are $5$ houses on a street,$A, B, C, D$ and $E$. For all cases,assume that positions to the right are positive.
$(i)$ Draw a frame of reference with house $A$ as the origin and the positions of houses $B, C, D$ and $E$.
$(ii)$ You live in house $C$. What is your position relative to house $E$?
$(iii)$ What are the positions of houses $A$ and $D$,if house $B$ is taken as the reference point?

(N/A) $(i)$ Taking house $A$ as the origin $(0 \ m)$,the positions of the houses are: $A = 0 \ m, B = 10 \ m, C = 20 \ m, D = 30 \ m, E = 40 \ m$.
$(ii)$ Position of house $C = 20 \ m$ and position of house $E = 40 \ m$. The position of $C$ relative to $E$ is $20 \ m - 40 \ m = -20 \ m$. This means house $C$ is $20 \ m$ to the left of house $E$.
$(iii)$ Taking house $B$ as the reference point $(0 \ m)$,the position of house $A$ is $-10 \ m$ and the position of house $D$ is $20 \ m$.