At 12 20, Neave left Town W for Town X, driving at a speed of 87 km/h. At 15 20, Billy also left Town W for Town X driving at a certain speed. Both of them did not change their speed throughout the journey. At 18 20, both of them passed a mall that was 261 km away from Town X. How many minutes earlier did Billy reach Town X than Neave?

Distance that Neave travelled
= 6 x 87
= 522 km

Distance between Town W and Town X
= 522 + 261
= 783 km

Since Billy passed the mall at the same time as Neave, it means that Billy travelled 522 km in 3 hours.

Billy's speed during the journey
= 522 ÷ 3
= 174 km/h

Duration that Billy took to reach Town X after passing the mall
= 261 ÷ 174
= 1.5 h

Duration that Neave took to reach Town X after passing the mall
= 261 ÷ 87
= 3 h

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

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

Billy reached Town X 90 minutes earlier than Neave.

Answer(s): 90 min