George and Daniel 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, George cycled faster than Daniel. He arrived at the finishing point 20 minutes before Daniel who was 5 km behind him. Daniel 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 George's average speed for the remaining 43 km of the trip in km/h?
(a)
60 min = 1 h
20 min =
2060 h =
13 Daniel's average speed
= 5 ÷
13 = 15 km/h
Time that Daniel took for the trip
= 48 ÷ 15
= 3
315 h
= 3
15 h
= 3 h 12 min
3 h 12 min before 09 30 is 06 18.
(b)
To find the time that George took for the remaining 43 km of the trip, we need to use the time that Daniel took subtract that of the time taken for first 5 km and the time that George was faster than Daniel.
Time that George took for the remaining 43 km of the trip
= 3
15 -
13 -
13 = 2
815 h
George's average speed
= 43 ÷ 2
815 = 16
3738 km/h
Answer(s): (a) 06 18; (b) 16
3738 km/h