\(60=20+(a \times 4)\)
\(a=\frac{60-20}{4}=10 \;km / h ^{2}\).
\(d=u t+\frac{1}{2} a t^{2}=(20 \times 4)+\frac{1}{2} \times 10 \times(4)^{2}=160 \;km\)
$\begin{array}{|c|c|c|c|c|} \hline t( s ) & 0 & 1 & 2 & 3 \\ \hline x ( m ) & -2 & 0 & 6 & 16 \\ \hline \end{array} $