City W and City X is 360 km apart. Reggie left City W for City X at 8.00 a.m. travelling at an average speed of 72 km/h. Tim left City W later than Reggie and caught up with him at 10.00 a.m. Tim was travelling at a speed of 108 km/h.

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

(a)
From 8.00 a.m. to 10.00 a.m. = 2 h

Distance that Reggie covered when Tim caught up with Reggie
= 2 x 72
= 144 km

Time that Tim took to travel 144 km
= 144 ÷ 108
= 1¹₃ h

1 h = 60 min
¹₃ h = ¹₃ x 60 = 20 min
1¹₃ h = 1 h 20 min

Time that Tim left City W:
1 h 20 min before 10.00 a.m. = 8.40 a.m.

(b)
Remaining distance that they had to cover to reach City X
= 360 - 144
= 216 km

Duration that Tim had to travel before reaching City X
= 216 ÷ 108
= 2 h

Duration that Reggie had to travel before reaching City X
= 216 ÷ 72
= 3 h

Duration that Reggie took to arrive later than Tim in City X
= 3 - 2
= 1 h

Answer(s): (a) 8.40 a.m.; (b) 1 h