Could someone check this because I have different answers to those given for parts ii and iii.
i) You want to use $\displaystyle a=\frac{\Delta v}{\Delta t}$. Your result will be in $\displaystyle \frac{\text{km}}{\text{min}\cdot\text{hr}}$. To make the required conversion to the units given use:
$\displaystyle x\frac{\text{km}}{\text{min}\cdot\text{hr}}\cdot \frac{1000\text{ m}}{1\text{ km}}\cdot\frac{1\text{ hr}}{3600\text{s}}\cdot\frac{1\text{ min}}{60\text{ s}}=\frac{x}{216}\,\frac{\text{m}}{\text{s}^2}$
ii) The area under the velocity function is two right triangles, a trapezoid and a rectangle. Then divide the area by 60 to convert the minutes to hours to get the result in km.
iii) Use $\displaystyle \bar{v}=\frac{d}{t}$