The last 20 km of the journey was driven at 80 km/h.<br><br>
Time = Distance &divide; Speed<br>
Time = 20 &divide; 80 = \( \frac{1}{4} \) hour<br>
\( \frac{1}{4} \) hour = \( \frac{1}{4} \) &times; 60 = 15 minutes.<br><br>
Final Answer: 15 min