Billy and Zane started on a 48-km cycling trip at the same time. They cycled at the same speed for first 5 km. For the remaining 43 km, Billy cycled faster than Zane. He arrived at the finishing point 20 minutes before Zane who was 5 km behind him. Zane 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 Billy's average speed for the remaining 43 km of the trip in km/h?
(a)
60 min = 1 h
20 min =
2060 h =
13 Zane's average speed
= 5 ÷
13 = 15 km/h
Time that Zane 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 Billy took for the remaining 43 km of the trip, we need to use the time that Zane took subtract that of the time taken for first 5 km and the time that Billy was faster than Zane.
Time that Billy took for the remaining 43 km of the trip
= 3
15 -
13 -
13 = 2
815 h
Billy's average speed
= 43 ÷ 2
815 = 16
3738 km/h
Answer(s): (a) 05 13; (b) 16
3738 km/h