City D and City E is 462 km apart. Oliver left City D for City E at 7.00 a.m. travelling at an average speed of 66 km/h. Will left City D later than Oliver and caught up with him at 9.00 a.m. Will was travelling at a speed of 72 km/h.

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

(a)
From 7.00 a.m. to 9.00 a.m. = 2 h

Distance that Oliver covered when Will caught up with Oliver
= 2 x 66
= 132 km

Time that Will took to travel 132 km
= 132 ÷ 72
= 1⁵₆ h

1 h = 60 min
⁵₆ h = ⁵₆ x 60 = 50 min
1⁵₆ h = 1 h 50 min

Time that Will left City D:
1 h 50 min before 9.00 a.m. = 7.10 a.m.

(b)
Remaining distance that they had to cover to reach City E
= 462 - 132
= 330 km

Duration that Will had to travel before reaching City E
= 330 ÷ 72
= 4⁷₁₂ h

Duration that Oliver had to travel before reaching City E
= 330 ÷ 66
= 5 h

Duration that Oliver took to arrive later than Will in City E
= 5 - 4⁷₁₂
= ⁵₁₂ h

Answer(s): (a) 7.10 a.m.; (b) ⁵₁₂ h