City T and City U is 432 km apart. Cody left City T for City U at 7.00 a.m. travelling at an average speed of 72 km/h. Riordan left City T later than Cody and caught up with him at 10.00 a.m. Riordan was travelling at a speed of 96 km/h.

1. At what time did Riordan leave City T?
2. How much later did Cody arrive in City U than Riordan? Express your answer in h as a fraction or mixed number.

(a)
From 7.00 a.m. to 10.00 a.m. = 3 h

Distance that Cody covered when Riordan caught up with Cody
= 3 x 72
= 216 km

Time that Riordan took to travel 216 km
= 216 ÷ 96
= 2¹₄ h

1 h = 60 min
¹₄ h = ¹₄ x 60 = 15 min
2¹₄ h = 2 h 15 min

Time that Riordan left City T:
2 h 15 min before 10.00 a.m. = 7.45 a.m.

(b)
Remaining distance that they had to cover to reach City U
= 432 - 216
= 216 km

Duration that Riordan had to travel before reaching City U
= 216 ÷ 96
= 2¹₄ h

Duration that Cody had to travel before reaching City U
= 216 ÷ 72
= 3 h

Duration that Cody took to arrive later than Riordan in City U
= 3 - 2¹₄
= ³₄ h

Answer(s): (a) 7.45 a.m.; (b) ³₄ h