Michael and Fabian started on a 48-km cycling trip at the same time. They cycled at the same speed for first 10 km. For the remaining 38 km, Michael cycled faster than Fabian. He arrived at the finishing point 40 minutes before Fabian who was 10 km behind him. Fabian did not change his speed throughout and completed it at 09 25.

1. At what time did the trip begin? Give the answer in 12-hour format.
2. What was Michael's average speed for the remaining 38 km of the trip in km/h?

(a)
60 min = 1 h
40 min =⁴⁰₆₀ h = ²₃ 

Fabian's average speed
= 10 ÷ ²₃
= 15 km/h

Time that Fabian took for the trip
= 48 ÷ 15
= 3³₁₅ h
= 3¹₅ h
= 3 h 12 min

3 h 12 min before 09 25 is 06 13.

(b)
To find the time that Michael took for the remaining 38 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 Michael was faster than Fabian.

Time that Michael took for the remaining 38 km of the trip
= 3¹₅ - ²₃ - ²₃
= 1¹³₁₅ h

Michael's average speed
= 38 ÷ 1¹³₁₅
= 20⁵₁₄ km/h

Answer(s): (a) 06 13; (b) 20⁵₁₄ km/h