At 13 45, Sam left Town K for Town L, driving at a speed of 77 km/h. At 15 45, Tim also left Town K for Town L driving at a certain speed. Both of them did not change their speed throughout the journey. At 17 45, both of them passed a mosque that was 231 km away from Town L. How many minutes earlier did Tim reach Town L than Sam?

Distance that Sam travelled
= 4 x 77
= 308 km

Distance between Town K and Town L
= 308 + 231
= 539 km

Since Tim passed the mosque at the same time as Sam, it means that Tim travelled 308 km in 2 hours.

Tim's speed during the journey
= 308 ÷ 2
= 154 km/h

Duration that Tim took to reach Town L after passing the mosque
= 231 ÷ 154
= 1.5 h

Duration that Sam took to reach Town L after passing the mosque
= 231 ÷ 77
= 3 h

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

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

Tim reached Town L 90 minutes earlier than Sam.

Answer(s): 90 min