Oliver and Fabian started on a 55-km cycling trip at the same time. They cycled at the same speed for first 10 km. For the remaining 45 km, Oliver cycled faster than Fabian. He arrived at the finishing point 24 minutes before Fabian who was 10 km behind him. Fabian did not change his speed throughout and completed it at 09 30.
- At what time did the trip begin? Give the answer in 12-hour format.
- What was Oliver's average speed for the remaining 45 km of the trip in km/h?
(a)
60 min = 1 h
24 min =
2460 h =
25 Fabian's average speed
= 10 ÷
25 = 25 km/h
Time that Fabian took for the trip
= 55 ÷ 25
= 2
525 h
= 2
15 h
= 2 h 12 min
2 h 12 min before 09 30 is 07 18.
(b)
To find the time that Oliver took for the remaining 45 km of the trip, we need to use the time that Fabian took subtract that of the time taken for first 10 km and the time that Oliver was faster than Fabian.
Time that Oliver took for the remaining 45 km of the trip
= 2
15 -
25 -
25 = 1
25 h
Oliver's average speed
= 45 ÷ 1
25 = 32
17 km/h
Answer(s): (a) 07 18; (b) 32
17 km/h