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