At 14 45, Dylan left Town Q for Town R, driving at a speed of 81 km/h. At 17 45, Howard also left Town Q for Town R driving at a certain speed. Both of them did not change their speed throughout the journey. At 20 45, both of them passed a market that was 243 km away from Town R. How many minutes earlier did Howard reach Town R than Dylan?

Distance that Dylan travelled
= 6 x 81
= 486 km

Distance between Town Q and Town R
= 486 + 243
= 729 km

Since Howard passed the market at the same time as Dylan, it means that Howard travelled 486 km in 3 hours.

Howard's speed during the journey
= 486 ÷ 3
= 162 km/h

Duration that Howard took to reach Town R after passing the market
= 243 ÷ 162
= 1.5 h

Duration that Dylan took to reach Town R after passing the market
= 243 ÷ 81
= 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

Howard reached Town R 90 minutes earlier than Dylan.

Answer(s): 90 min