City L and City M is 560 km apart. Jenson left City L for City M at 9.00 a.m. travelling at an average speed of 80 km/h. Warren left City L later than Jenson and caught up with him at 12.00 p.m. Warren was travelling at a speed of 90 km/h.

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

(a)
From 9.00 a.m. to 12.00 p.m. = 3 h

Distance that Jenson covered when Warren caught up with Jenson
= 3 x 80
= 240 km

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

(b)
Remaining distance that they had to cover to reach City M
= 560 - 240
= 320 km

Duration that Warren had to travel before reaching City M
= 320 ÷ 90
= 3⁵₉ h

Duration that Jenson had to travel before reaching City M
= 320 ÷ 80
= 4 h

Duration that Jenson took to arrive later than Warren in City M
= 4 - 3⁵₉
= ⁴₉ h

Answer(s): (a) 9.20 a.m.; (b) ⁴₉ h