City K and City L is 518 km apart. Ian left City K for City L at 9.00 a.m. travelling at an average speed of 74 km/h. Sean left City K later than Ian and caught up with him at 11.00 a.m. Sean was travelling at a speed of 111 km/h.

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

(a)
From 9.00 a.m. to 11.00 a.m. = 2 h

Distance that Ian covered when Sean caught up with Ian
= 2 x 74
= 148 km

Time that Sean took to travel 148 km
= 148 ÷ 111
= 1¹₃ h

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

Time that Sean left City K:
1 h 20 min before 11.00 a.m. = 9.40 a.m.

(b)
Remaining distance that they had to cover to reach City L
= 518 - 148
= 370 km

Duration that Sean had to travel before reaching City L
= 370 ÷ 111
= 3¹₃ h

Duration that Ian had to travel before reaching City L
= 370 ÷ 74
= 5 h

Duration that Ian took to arrive later than Sean in City L
= 5 - 3¹₃
= 1²₃ h

Answer(s): (a) 9.40 a.m.; (b) 1²₃ h