City V and City W is 512 km apart. Ryan left City V for City W at 8.00 a.m. travelling at an average speed of 64 km/h. Ian left City V later than Ryan and caught up with him at 11.00 a.m. Ian was travelling at a speed of 72 km/h.

1. At what time did Ian leave City V?
2. How much later did Ryan arrive in City W than Ian? Express your answer in h as a fraction or mixed number.

(a)
From 8.00 a.m. to 11.00 a.m. = 3 h

Distance that Ryan covered when Ian caught up with Ryan
= 3 x 64
= 192 km

Time that Ian took to travel 192 km
= 192 ÷ 72
= 2²₃ h

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

Time that Ian left City V:
2 h 40 min before 11.00 a.m. = 8.20 a.m.

(b)
Remaining distance that they had to cover to reach City W
= 512 - 192
= 320 km

Duration that Ian had to travel before reaching City W
= 320 ÷ 72
= 4⁴₉ h

Duration that Ryan had to travel before reaching City W
= 320 ÷ 64
= 5 h

Duration that Ryan took to arrive later than Ian in City W
= 5 - 4⁴₉
= ⁵₉ h

Answer(s): (a) 8.20 a.m.; (b) ⁵₉ h