City K and City L is 483 km apart. Julian left City K for City L at 7.00 a.m. travelling at an average speed of 69 km/h. Ken left City K later than Julian and caught up with him at 9.00 a.m. Ken was travelling at a speed of 72 km/h.

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

(a)
From 7.00 a.m. to 9.00 a.m. = 2 h

Distance that Julian covered when Ken caught up with Julian
= 2 x 69
= 138 km

Time that Ken took to travel 138 km
= 138 ÷ 72
= 1¹¹₁₂ h

1 h = 60 min
¹¹₁₂ h = ¹¹₁₂ x 60 = 55 min
1¹¹₁₂ h = 1 h 55 min

Time that Ken left City K:
1 h 55 min before 9.00 a.m. = 7.05 a.m.

(b)
Remaining distance that they had to cover to reach City L
= 483 - 138
= 345 km

Duration that Ken had to travel before reaching City L
= 345 ÷ 72
= 4¹⁹₂₄ h

Duration that Julian had to travel before reaching City L
= 345 ÷ 69
= 5 h

Duration that Julian took to arrive later than Ken in City L
= 5 - 4¹⁹₂₄
= ⁵₂₄ h

Answer(s): (a) 7.05 a.m.; (b) ⁵₂₄ h