At 14 10, Riordan left Town B for Town C, driving at a speed of 84 km/h. At 16 10, Julian also left Town B for Town C driving at a certain speed. Both of them did not change their speed throughout the journey. At 19 10, both of them passed a mall that was 252 km away from Town C. How many minutes earlier did Julian reach Town C than Riordan?

Distance that Riordan travelled
= 5 x 84
= 420 km

Distance between Town B and Town C
= 420 + 252
= 672 km

Since Julian passed the mall at the same time as Riordan, it means that Julian travelled 420 km in 3 hours.

Julian's speed during the journey
= 420 ÷ 3
= 140 km/h

Duration that Julian took to reach Town C after passing the mall
= 252 ÷ 140
= 1.8 h

Duration that Riordan took to reach Town C after passing the mall
= 252 ÷ 84
= 3 h

Difference between the time they took to reach Town C
= 3 - 1.8
= 1.2 h

1 h = 60 min
1.2 h = 1.2 x 60 = 72 min

Julian reached Town C 72 minutes earlier than Riordan.

Answer(s): 72 min