City D and City E is 360 km apart. Fabian left City D for City E at 8.00 a.m. travelling at an average speed of 60 km/h. Carl left City D later than Fabian and caught up with him at 12.00 p.m. Carl was travelling at a speed of 90 km/h.

1. At what time did Carl leave City D?
2. How much later did Fabian arrive in City E than Carl? Express your answer in h as a fraction or mixed number.

(a)
From 8.00 a.m. to 12.00 p.m. = 4 h

Distance that Fabian covered when Carl caught up with Fabian
= 4 x 60
= 240 km

Time that Carl took to travel 240 km
= 240 ÷ 90
= 2²₃ h

1 h = 60 min
²₃ h = ²₃ x 60 = 40 min
2²₃ h = 2 h 40 min

Time that Carl left City D:
2 h 40 min before 12.00 p.m. = 9.20 a.m.

(b)
Remaining distance that they had to cover to reach City E
= 360 - 240
= 120 km

Duration that Carl had to travel before reaching City E
= 120 ÷ 90
= 1¹₃ h

Duration that Fabian had to travel before reaching City E
= 120 ÷ 60
= 2 h

Duration that Fabian took to arrive later than Carl in City E
= 2 - 1¹₃
= ²₃ h

Answer(s): (a) 9.20 a.m.; (b) ²₃ h