At 13 30, Oliver left Town D for Town E, driving at a speed of 60 km/h. At 16 30, Oscar also left Town D for Town E driving at a certain speed. Both of them did not change their speed throughout the journey. At 19 30, both of them passed a museum that was 180 km away from Town E. How many minutes earlier did Oscar reach Town E than Oliver?

Distance that Oliver travelled
= 6 x 60
= 360 km

Distance between Town D and Town E
= 360 + 180
= 540 km

Since Oscar passed the museum at the same time as Oliver, it means that Oscar travelled 360 km in 3 hours.

Oscar's speed during the journey
= 360 ÷ 3
= 120 km/h

Duration that Oscar took to reach Town E after passing the museum
= 180 ÷ 120
= 1.5 h

Duration that Oliver took to reach Town E after passing the museum
= 180 ÷ 60
= 3 h

Difference between the time they took to reach Town E
= 3 - 1.5
= 1.5 h

1 h = 60 min
1.5 h = 1.5 x 60 = 90 min

Oscar reached Town E 90 minutes earlier than Oliver.

Answer(s): 90 min