Henry and Jenson started on a 48-km cycling trip at the same time. They cycled at the same speed for first 10 km. For the remaining 38 km, Henry cycled faster than Jenson. He arrived at the finishing point 40 minutes before Jenson who was 10 km behind him. Jenson did not change his speed throughout and completed it at 08 25.
- At what time did the trip begin? Give the answer in 12-hour format.
- What was Henry's average speed for the remaining 38 km of the trip in km/h?
(a)
60 min = 1 h
40 min =
4060 h =
23 Jenson's average speed
= 10 ÷
23 = 15 km/h
Time that Jenson took for the trip
= 48 ÷ 15
= 3
315 h
= 3
15 h
= 3 h 12 min
3 h 12 min before 08 25 is 05 13.
(b)
To find the time that Henry took for the remaining 38 km of the trip, we need to use the time that Jenson took subtract that of the time taken for first 10 km and the time that Henry was faster than Jenson.
Time that Henry took for the remaining 38 km of the trip
= 3
15 -
23 -
23 = 1
1315 h
Henry's average speed
= 38 ÷ 1
1315 = 20
514 km/h
Answer(s): (a) 05 13; (b) 20
514 km/h