City K and City L is 540 km apart. Pierre left City K for City L at 8.00 a.m. travelling at an average speed of 60 km/h. Flynn left City K later than Pierre and caught up with him at 12.00 p.m. Flynn was travelling at a speed of 90 km/h.

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

(a)
From 8.00 a.m. to 12.00 p.m. = 4 h

Distance that Pierre covered when Flynn caught up with Pierre
= 4 x 60
= 240 km

Time that Flynn took to travel 240 km
= 240 ÷ 90
= 2²₃ h

1 h = 60 min
²₃ h = ²₃ x 60 = 40 min
2²₃ h = 2 h 40 min

Time that Flynn left City K:
2 h 40 min before 12.00 p.m. = 9.20 a.m.

(b)
Remaining distance that they had to cover to reach City L
= 540 - 240
= 300 km

Duration that Flynn had to travel before reaching City L
= 300 ÷ 90
= 3¹₃ h

Duration that Pierre had to travel before reaching City L
= 300 ÷ 60
= 5 h

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

Answer(s): (a) 9.20 a.m.; (b) 1²₃ h