At 13 10, Valen left Town V for Town W, driving at a speed of 70 km/h. At 15 10, David also left Town V for Town W driving at a certain speed. Both of them did not change their speed throughout the journey. At 17 10, both of them passed a bistro that was 210 km away from Town W. How many minutes earlier did David reach Town W than Valen?

Distance that Valen travelled
= 4 x 70
= 280 km

Distance between Town V and Town W
= 280 + 210
= 490 km

Since David passed the bistro at the same time as Valen, it means that David travelled 280 km in 2 hours.

David's speed during the journey
= 280 ÷ 2
= 140 km/h

Duration that David took to reach Town W after passing the bistro
= 210 ÷ 140
= 1.5 h

Duration that Valen took to reach Town W after passing the bistro
= 210 ÷ 70
= 3 h

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

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

David reached Town W 90 minutes earlier than Valen.

Answer(s): 90 min