At 11 15, Andy left Town H for Town J, driving at a speed of 63 km/h. At 12 15, Luke also left Town H for Town J driving at a certain speed. Both of them did not change their speed throughout the journey. At 15 15, both of them passed a school that was 126 km away from Town J. How many minutes earlier did Luke reach Town J than Andy?

Distance that Andy travelled
= 4 x 63
= 252 km

Distance between Town H and Town J
= 252 + 126
= 378 km

Since Luke passed the school at the same time as Andy, it means that Luke travelled 252 km in 3 hours.

Luke's speed during the journey
= 252 ÷ 3
= 84 km/h

Duration that Luke took to reach Town J after passing the school
= 126 ÷ 84
= 1.5 h

Duration that Andy took to reach Town J after passing the school
= 126 ÷ 63
= 2 h

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

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

Luke reached Town J 30 minutes earlier than Andy.

Answer(s): 30 min