At 10 40, Howard left Town A for Town B, driving at a speed of 64 km/h. At 11 40, Ben also left Town A for Town B driving at a certain speed. Both of them did not change their speed throughout the journey. At 15 40, both of them passed a market that was 128 km away from Town B. How many minutes earlier did Ben reach Town B than Howard?

Distance that Howard travelled
= 5 x 64
= 320 km

Distance between Town A and Town B
= 320 + 128
= 448 km

Since Ben passed the market at the same time as Howard, it means that Ben travelled 320 km in 4 hours.

Ben's speed during the journey
= 320 ÷ 4
= 80 km/h

Duration that Ben took to reach Town B after passing the market
= 128 ÷ 80
= 1.6 h

Duration that Howard took to reach Town B after passing the market
= 128 ÷ 64
= 2 h

Difference between the time they took to reach Town B
= 2 - 1.6
= 0.4 h

1 h = 60 min
0.4 h = 0.4 x 60 = 24 min

Ben reached Town B 24 minutes earlier than Howard.

Answer(s): 24 min