At 12 10, Ken left Town A for Town B, driving at a speed of 70 km/h. At 15 10, Fred also left Town A for Town B driving at a certain speed. Both of them did not change their speed throughout the journey. At 17 10, both of them passed a bistro that was 280 km away from Town B. How many minutes earlier did Fred reach Town B than Ken?
Duration that Ken travelled from 12 10 to 17 10 = 5 h
Distance that Ken travelled
= 5 x 70
= 350 km
Distance between Town A and Town B
= 350 + 280
= 630 km
Since Fred passed the bistro at the same time as Ken, it means that Fred travelled 350 km in 2 hours.
Fred's speed during the journey
= 350 ÷ 2
= 175 km/h
Duration that Fred took to reach Town B after passing the bistro
= 280 ÷ 175
= 1.6 h
Duration that Ken took to reach Town B after passing the bistro
= 280 ÷ 70
= 4 h
Difference between the time they took to reach Town B
= 4 - 1.6
= 2.4 h
1 h = 60 min
2.4 h = 2.4 x 60 = 144 min
Fred reached Town B 144 minutes earlier than Ken.
Answer(s): 144 min
