=$=\frac{1}{2}\times 0.2\times {\left(60\right)}^2=\frac{1}{\cancel{2}}\times \frac{\cancel{2}}{\cancel{10}}\times \cancel{60}\times 60=360m$

‘S’ is the distance travelled by the first car in 1min

${\text{S}}_{\text{2}}-{\text{S}}_{\text{1}}=\text{3S}$

$\frac{1}{2}\times \left(0.2\right)\times {\left(t+60\right)}^2-\frac{1}{2}\left(0.2\right)t^2=3\times 360$

Where ${\text{S}}_{\text{2}}$ is the distance travelled by the first car and ${\text{S}}_{\text{1}}$ is the distance travelled by the second car

$\frac{1}{\cancel{2}}\left[{\cancel{0.2}}^{0.1}\right]\left[{\left(t+60\right)}^2-t^2\right]=1080$

$0.1\left[\cancel{t^2}+3600+120t-\cancel{t^2}\right]=1080$

$0.\text{1}\left(\text{36}00+\text{12}0\text{t}\right)=\text{1}0\text{8}0$

$\text{36}0+\text{12t}=\text{1}0\text{8}0$

$\text{12t=1}0\text{8}0-\text{36}0=\text{72}0$

$\text{12t}=\text{72}0$

$t=\frac{{\cancel{720}}^{60S}}{\cancel{12}}$        

$\begin{array}{}t=1\min \end{array}$