At 14 30, Pierre left Town H for Town J, driving at a speed of 78 km/h. At 15 30, Neave also left Town H for Town J driving at a certain speed. Both of them did not change their speed throughout the journey. At 18 30, both of them passed a library that was 156 km away from Town J. How many minutes earlier did Neave reach Town J than Pierre?
Duration that Pierre travelled from 14 30 to 18 30 = 4 h
Distance that Pierre travelled
= 4 x 78
= 312 km
Distance between Town H and Town J
= 312 + 156
= 468 km
Since Neave passed the library at the same time as Pierre, it means that Neave travelled 312 km in 3 hours.
Neave's speed during the journey
= 312 ÷ 3
= 104 km/h
Duration that Neave took to reach Town J after passing the library
= 156 ÷ 104
= 1.5 h
Duration that Pierre took to reach Town J after passing the library
= 156 ÷ 78
= 2 h
Difference between the time they took to reach Town J
= 2 - 1.5
= 0.5 h
1 h = 60 min
0.5 h = 0.5 x 60 = 30 min
Neave reached Town J 30 minutes earlier than Pierre.
Answer(s): 30 min
