At 11 30, Vaidev left Town N for Town P, driving at a speed of 70 km/h. At 14 30, David also left Town N for Town P driving at a certain speed. Both of them did not change their speed throughout the journey. At 17 30, both of them passed a bakery that was 210 km away from Town P. How many minutes earlier did David reach Town P than Vaidev?
Duration that Vaidev travelled from 11 30 to 17 30 = 6 h
Distance that Vaidev travelled
= 6 x 70
= 420 km
Distance between Town N and Town P
= 420 + 210
= 630 km
Since David passed the bakery at the same time as Vaidev, it means that David travelled 420 km in 3 hours.
David's speed during the journey
= 420 ÷ 3
= 140 km/h
Duration that David took to reach Town P after passing the bakery
= 210 ÷ 140
= 1.5 h
Duration that Vaidev took to reach Town P after passing the bakery
= 210 ÷ 70
= 3 h
Difference between the time they took to reach Town P
= 3 - 1.5
= 1.5 h
1 h = 60 min
1.5 h = 1.5 x 60 = 90 min
David reached Town P 90 minutes earlier than Vaidev.
Answer(s): 90 min
