At 10 45, Ken left Town H for Town J, driving at a speed of 86 km/h. At 12 45, Jack also left Town H for Town J driving at a certain speed. Both of them did not change their speed throughout the journey. At 14 45, both of them passed a bistro that was 258 km away from Town J. How many minutes earlier did Jack reach Town J than Ken?

Distance that Ken travelled
= 4 x 86
= 344 km

Distance between Town H and Town J
= 344 + 258
= 602 km

Since Jack passed the bistro at the same time as Ken, it means that Jack travelled 344 km in 2 hours.

Jack's speed during the journey
= 344 ÷ 2
= 172 km/h

Duration that Jack took to reach Town J after passing the bistro
= 258 ÷ 172
= 1.5 h

Duration that Ken took to reach Town J after passing the bistro
= 258 ÷ 86
= 3 h

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

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

Jack reached Town J 90 minutes earlier than Ken.

Answer(s): 90 min