At 11 30, Lee left Town F for Town G, driving at a speed of 80 km/h. At 13 30, Zeph also left Town F for Town G driving at a certain speed. Both of them did not change their speed throughout the journey. At 15 30, both of them passed a cinema that was 240 km away from Town G. How many minutes earlier did Zeph reach Town G than Lee?

Distance that Lee travelled
= 4 x 80
= 320 km

Distance between Town F and Town G
= 320 + 240
= 560 km

Since Zeph passed the cinema at the same time as Lee, it means that Zeph travelled 320 km in 2 hours.

Zeph's speed during the journey
= 320 ÷ 2
= 160 km/h

Duration that Zeph took to reach Town G after passing the cinema
= 240 ÷ 160
= 1.5 h

Duration that Lee took to reach Town G after passing the cinema
= 240 ÷ 80
= 3 h

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

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

Zeph reached Town G 90 minutes earlier than Lee.

Answer(s): 90 min