City E and City F is 252 km apart. Bryan left City E for City F at 10.00 a.m. travelling at an average speed of 63 km/h. Ian left City E later than Bryan and caught up with him at 12.00 p.m. Ian was travelling at a speed of 84 km/h.

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

(a)
From 10.00 a.m. to 12.00 p.m. = 2 h

Distance that Bryan covered when Ian caught up with Bryan
= 2 x 63
= 126 km

Time that Ian took to travel 126 km
= 126 ÷ 84
= 1¹₂ h

1 h = 60 min
¹₂ h = ¹₂ x 60 = 30 min
1¹₂ h = 1 h 30 min

Time that Ian left City E:
1 h 30 min before 12.00 p.m. = 10.30 a.m.

(b)
Remaining distance that they had to cover to reach City F
= 252 - 126
= 126 km

Duration that Ian had to travel before reaching City F
= 126 ÷ 84
= 1¹₂ h

Duration that Bryan had to travel before reaching City F
= 126 ÷ 63
= 2 h

Duration that Bryan took to arrive later than Ian in City F
= 2 - 1¹₂
= ¹₂ h

Answer(s): (a) 10.30 a.m.; (b) ¹₂ h