City N and City P is 384 km apart. Flynn left City N for City P at 7.00 a.m. travelling at an average speed of 64 km/h. Julian left City N later than Flynn and caught up with him at 10.00 a.m. Julian was travelling at a speed of 72 km/h.

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

(a)
From 7.00 a.m. to 10.00 a.m. = 3 h

Distance that Flynn covered when Julian caught up with Flynn
= 3 x 64
= 192 km

Time that Julian took to travel 192 km
= 192 ÷ 72
= 2²₃ h

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

Time that Julian left City N:
2 h 40 min before 10.00 a.m. = 7.20 a.m.

(b)
Remaining distance that they had to cover to reach City P
= 384 - 192
= 192 km

Duration that Julian had to travel before reaching City P
= 192 ÷ 72
= 2²₃ h

Duration that Flynn had to travel before reaching City P
= 192 ÷ 64
= 3 h

Duration that Flynn took to arrive later than Julian in City P
= 3 - 2²₃
= ¹₃ h

Answer(s): (a) 7.20 a.m.; (b) ¹₃ h