Five years ago,the sum of the ages of a father and two sons was $x$ years. Then,after five years,the sum of the ages of all will be $\ldots \ldots \ldots$ years.

$A$ mother tells her son,"Five years ago,$I$ was five times as old as you were. After ten years,$I$ will be two times as old as you will be." Represent this situation as a pair of linear equations in two variables.

Use the method of elimination to find the solution of the following pair of linear equations: $2x + y = 4$ and $x + 3y = 7$.

Solve the following pair of linear equations by the method of substitution: $8x - 3y = 1$ and $34x - 3y = 14$.

Ankita travels $14 \,km$ to her home partly by rickshaw and partly by bus. She takes half an $hour$ if she travels $2 \,km$ by rickshaw and the remaining distance by bus. On the other hand,if she travels $4 \,km$ by rickshaw and the remaining distance by bus,she takes $9 \,minutes$ longer. Find the speed of the rickshaw and of the bus (in $km/h$).

The diagram given below shows two sticks $-$ one $BLACK$ and the other $WHITE$. Based on the measurements shown,what is the length of the white stick? (in $cm$)