At 13 55, Liam left Town L for Town M, driving at a speed of 84 km/h. At 16 55, Lee also left Town L for Town M driving at a certain speed. Both of them did not change their speed throughout the journey. At 19 55, both of them passed a museum that was 252 km away from Town M. How many minutes earlier did Lee reach Town M than Liam?

Distance that Liam travelled
= 6 x 84
= 504 km

Distance between Town L and Town M
= 504 + 252
= 756 km

Since Lee passed the museum at the same time as Liam, it means that Lee travelled 504 km in 3 hours.

Lee's speed during the journey
= 504 ÷ 3
= 168 km/h

Duration that Lee took to reach Town M after passing the museum
= 252 ÷ 168
= 1.5 h

Duration that Liam took to reach Town M after passing the museum
= 252 ÷ 84
= 3 h

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

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

Lee reached Town M 90 minutes earlier than Liam.

Answer(s): 90 min