At 11 35, Sean left Town E for Town F, driving at a speed of 64 km/h. At 13 35, Japheth also left Town E for Town F driving at a certain speed. Both of them did not change their speed throughout the journey. At 15 35, both of them passed a hypermart that was 192 km away from Town F. How many minutes earlier did Japheth reach Town F than Sean?

Distance that Sean travelled
= 4 x 64
= 256 km

Distance between Town E and Town F
= 256 + 192
= 448 km

Since Japheth passed the hypermart at the same time as Sean, it means that Japheth travelled 256 km in 2 hours.

Japheth's speed during the journey
= 256 ÷ 2
= 128 km/h

Duration that Japheth took to reach Town F after passing the hypermart
= 192 ÷ 128
= 1.5 h

Duration that Sean took to reach Town F after passing the hypermart
= 192 ÷ 64
= 3 h

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

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

Japheth reached Town F 90 minutes earlier than Sean.

Answer(s): 90 min