At 11 55, George left Town T for Town U, driving at a speed of 60 km/h. At 13 55, Seth also left Town T for Town U driving at a certain speed. Both of them did not change their speed throughout the journey. At 15 55, both of them passed a clinic that was 180 km away from Town U. How many minutes earlier did Seth reach Town U than George?

Distance that George travelled
= 4 x 60
= 240 km

Distance between Town T and Town U
= 240 + 180
= 420 km

Since Seth passed the clinic at the same time as George, it means that Seth travelled 240 km in 2 hours.

Seth's speed during the journey
= 240 ÷ 2
= 120 km/h

Duration that Seth took to reach Town U after passing the clinic
= 180 ÷ 120
= 1.5 h

Duration that George took to reach Town U after passing the clinic
= 180 ÷ 60
= 3 h

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

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

Seth reached Town U 90 minutes earlier than George.

Answer(s): 90 min