At 11 40, Henry left Town M for Town N, driving at a speed of 77 km/h. At 14 40, Flynn also left Town M for Town N driving at a certain speed. Both of them did not change their speed throughout the journey. At 17 40, both of them passed a cafe that was 231 km away from Town N. How many minutes earlier did Flynn reach Town N than Henry?

Distance that Henry travelled
= 6 x 77
= 462 km

Distance between Town M and Town N
= 462 + 231
= 693 km

Since Flynn passed the cafe at the same time as Henry, it means that Flynn travelled 462 km in 3 hours.

Flynn's speed during the journey
= 462 ÷ 3
= 154 km/h

Duration that Flynn took to reach Town N after passing the cafe
= 231 ÷ 154
= 1.5 h

Duration that Henry took to reach Town N after passing the cafe
= 231 ÷ 77
= 3 h

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

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

Flynn reached Town N 90 minutes earlier than Henry.

Answer(s): 90 min