At 12 10, Warren left Town N for Town P, driving at a speed of 81 km/h. At 14 10, Justin also left Town N for Town P driving at a certain speed. Both of them did not change their speed throughout the journey. At 17 10, both of them passed a hospital that was 243 km away from Town P. How many minutes earlier did Justin reach Town P than Warren?

Distance that Warren travelled
= 5 x 81
= 405 km

Distance between Town N and Town P
= 405 + 243
= 648 km

Since Justin passed the hospital at the same time as Warren, it means that Justin travelled 405 km in 3 hours.

Justin's speed during the journey
= 405 ÷ 3
= 135 km/h

Duration that Justin took to reach Town P after passing the hospital
= 243 ÷ 135
= 1.8 h

Duration that Warren took to reach Town P after passing the hospital
= 243 ÷ 81
= 3 h

Difference between the time they took to reach Town P
= 3 - 1.8
= 1.2 h

1 h = 60 min
1.2 h = 1.2 x 60 = 72 min

Justin reached Town P 72 minutes earlier than Warren.

Answer(s): 72 min