Given the graph in the attached image;
a.
We want to find the speed during the first four AB and the second hour BC.
Let us write out the coordinates of A,B and C on the graph;
[tex]\begin{gathered} A=(0,0) \\ B=(1,10) \\ C=(2,15) \end{gathered}[/tex]
The speed for each hour is the slope of the line within that time.
So, the slope of line AB is;
[tex]\begin{gathered} m_{AB}=\frac{\Delta y}{\Delta x}=\frac{10-0}{1-0} \\ m_{AB}=10\text{ km/h} \end{gathered}[/tex]
the slope of line BC is;
[tex]\begin{gathered} m_{BC}=\frac{15-10}{2-1}=\frac{5}{1} \\ m_{BC}=5\text{ km/h} \end{gathered}[/tex]
Therefore, the speed at the first hour AB is;
[tex]10\text{ km/h}[/tex]
The speed at the second hour BC is;
[tex]5\text{ km/h}[/tex]
b.
Comparing the speed in the first hour AB to the speed in the second hour BC as calculated in question a above.
We can see that the speed in the first hour is more than the speed in the second hour.
The speed between A and B is double the speed between B and C.
Since the speed between A and B is 10 km/h and the speed between B and C is 5 km/h, so the speed between A and B is double the speed between B and C.
