At 14 20, Ian left Town H for Town J, driving at a speed of 61 km/h. At 17 20, Zeph also left Town H for Town J driving at a certain speed. Both of them did not change their speed throughout the journey. At 20 20, both of them passed a school that was 183 km away from Town J. How many minutes earlier did Zeph reach Town J than Ian?
Duration that Ian travelled from 14 20 to 20 20 = 6 h
Distance that Ian travelled
= 6 x 61
= 366 km
Distance between Town H and Town J
= 366 + 183
= 549 km
Since Zeph passed the school at the same time as Ian, it means that Zeph travelled 366 km in 3 hours.
Zeph's speed during the journey
= 366 ÷ 3
= 122 km/h
Duration that Zeph took to reach Town J after passing the school
= 183 ÷ 122
= 1.5 h
Duration that Ian took to reach Town J after passing the school
= 183 ÷ 61
= 3 h
Difference between the time they took to reach Town J
= 3 - 1.5
= 1.5 h
1 h = 60 min
1.5 h = 1.5 x 60 = 90 min
Zeph reached Town J 90 minutes earlier than Ian.
Answer(s): 90 min
