At 11 30, Lee left Town K for Town L, driving at a speed of 93 km/h. At 12 30, Mark also left Town K for Town L driving at a certain speed. Both of them did not change their speed throughout the journey. At 15 30, both of them passed a playground that was 186 km away from Town L. How many minutes earlier did Mark reach Town L than Lee?
Duration that Lee travelled from 11 30 to 15 30 = 4 h
Distance that Lee travelled
= 4 x 93
= 372 km
Distance between Town K and Town L
= 372 + 186
= 558 km
Since Mark passed the playground at the same time as Lee, it means that Mark travelled 372 km in 3 hours.
Mark's speed during the journey
= 372 ÷ 3
= 124 km/h
Duration that Mark took to reach Town L after passing the playground
= 186 ÷ 124
= 1.5 h
Duration that Lee took to reach Town L after passing the playground
= 186 ÷ 93
= 2 h
Difference between the time they took to reach Town L
= 2 - 1.5
= 0.5 h
1 h = 60 min
0.5 h = 0.5 x 60 = 30 min
Mark reached Town L 30 minutes earlier than Lee.
Answer(s): 30 min
