At 10 50, Vaidev left Town L for Town M, driving at a speed of 73 km/h. At 12 50, Harry also left Town L for Town M driving at a certain speed. Both of them did not change their speed throughout the journey. At 14 50, both of them passed a school that was 219 km away from Town M. How many minutes earlier did Harry reach Town M than Vaidev?

Distance that Vaidev travelled
= 4 x 73
= 292 km

Distance between Town L and Town M
= 292 + 219
= 511 km

Since Harry passed the school at the same time as Vaidev, it means that Harry travelled 292 km in 2 hours.

Harry's speed during the journey
= 292 ÷ 2
= 146 km/h

Duration that Harry took to reach Town M after passing the school
= 219 ÷ 146
= 1.5 h

Duration that Vaidev took to reach Town M after passing the school
= 219 ÷ 73
= 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

Harry reached Town M 90 minutes earlier than Vaidev.

Answer(s): 90 min