Daniel and Vaidev started on a 55-km cycling trip at the same time. They cycled at the same speed for first 5 km. For the remaining 50 km, Daniel cycled faster than Vaidev. He arrived at the finishing point 12 minutes before Vaidev who was 5 km behind him. Vaidev 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 Daniel's average speed for the remaining 50 km of the trip in km/h?
(a)
60 min = 1 h
12 min =
1260 h =
15 Vaidev's average speed
= 5 ÷
15 = 25 km/h
Time that Vaidev 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 Daniel took for the remaining 50 km of the trip, we need to use the time that Vaidev took subtract that of the time taken for first 5 km and the time that Daniel was faster than Vaidev.
Time that Daniel took for the remaining 50 km of the trip
= 2
15 -
15 -
15 = 1
45 h
Daniel's average speed
= 50 ÷ 1
45 = 27
79 km/h
Answer(s): (a) 07 18; (b) 27
79 km/h