At 11 40, Cole left Town Q for Town R, driving at a speed of 73 km/h. At 13 40, Billy also left Town Q for Town R driving at a certain speed. Both of them did not change their speed throughout the journey. At 15 40, both of them passed a salon that was 219 km away from Town R. How many minutes earlier did Billy reach Town R than Cole?

Distance that Cole travelled
= 4 x 73
= 292 km

Distance between Town Q and Town R
= 292 + 219
= 511 km

Since Billy passed the salon at the same time as Cole, it means that Billy travelled 292 km in 2 hours.

Billy's speed during the journey
= 292 ÷ 2
= 146 km/h

Duration that Billy took to reach Town R after passing the salon
= 219 ÷ 146
= 1.5 h

Duration that Cole took to reach Town R after passing the salon
= 219 ÷ 73
= 3 h

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

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

Billy reached Town R 90 minutes earlier than Cole.

Answer(s): 90 min