A van travelled at an average speed of 60 km/h from Town P to Town Q. An hour and a half later, a car started out towards the same destination at an average speed pf 75 km/h, reaching Town Q at the same time as the van.
(a) How long did the car take to travel from Town P to Town Q?
(b) If both the van and the car arrived at Town Q at 0630, at what time did the van start out?
Originally posted by kkhing:A van travelled at an average speed of 60 km/h from Town P to Town Q. An hour and a half later, a car started out towards the same destination at an average speed pf 75 km/h, reaching Town Q at the same time as the van.
(a) How long did the car take to travel from Town P to Town Q?
(b) If both the van and the car arrived at Town Q at 0630, at what time did the van start out?
A hour and a half later, distance van travelled
= 60km X 3/2 hours
= 90km.
Hence, distance between van and car = 90km
Speed of car is 15km/h faster than van.
Amount of time for car to reach van
= 90km/h / 15km/h
= 6hours
Hence, time taken for car = 6 hours.
time taken for van = 6 hours + 1 and half hours = 7 and half hours
Time which van start out
= 0630 - ( 7 and half hours )
= 2300