At 10 20, David left Town R for Town S, driving at a speed of 84 km/h. At 11 20, Sam also left Town R for Town S driving at a certain speed. Both of them did not change their speed throughout the journey. At 14 20, both of them passed a temple that was 168 km away from Town S. How many minutes earlier did Sam reach Town S than David?

Distance that David travelled
= 4 x 84
= 336 km

Distance between Town R and Town S
= 336 + 168
= 504 km

Since Sam passed the temple at the same time as David, it means that Sam travelled 336 km in 3 hours.

Sam's speed during the journey
= 336 ÷ 3
= 112 km/h

Duration that Sam took to reach Town S after passing the temple
= 168 ÷ 112
= 1.5 h

Duration that David took to reach Town S after passing the temple
= 168 ÷ 84
= 2 h

Difference between the time they took to reach Town S
= 2 - 1.5
= 0.5 h

1 h = 60 min
0.5 h = 0.5 x 60 = 30 min

Sam reached Town S 30 minutes earlier than David.

Answer(s): 30 min