City C and City D is 480 km apart. Zane left City C for City D at 10.00 a.m. travelling at an average speed of 80 km/h. Julian left City C later than Zane and caught up with him at 1.00 p.m. Julian was travelling at a speed of 90 km/h.

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

(a)
From 10.00 a.m. to 1.00 p.m. = 3 h

Distance that Zane covered when Julian caught up with Zane
= 3 x 80
= 240 km

Time that Julian 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 Julian left City C:
2 h 40 min before 1.00 p.m. = 10.20 a.m.

(b)
Remaining distance that they had to cover to reach City D
= 480 - 240
= 240 km

Duration that Julian had to travel before reaching City D
= 240 ÷ 90
= 2²₃ h

Duration that Zane had to travel before reaching City D
= 240 ÷ 80
= 3 h

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

Answer(s): (a) 10.20 a.m.; (b) ¹₃ h