City K and City L is 300 km apart. Ahmad left City K for City L at 10.00 a.m. travelling at an average speed of 60 km/h. Vaidev left City K later than Ahmad and caught up with him at 1.00 p.m. Vaidev was travelling at a speed of 72 km/h.

1. At what time did Vaidev leave City K?
2. How much later did Ahmad arrive in City L than Vaidev? 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 Ahmad covered when Vaidev caught up with Ahmad
= 3 x 60
= 180 km

Time that Vaidev took to travel 180 km
= 180 ÷ 72
= 2¹₂ h

1 h = 60 min
¹₂ h = ¹₂ x 60 = 30 min
2¹₂ h = 2 h 30 min

Time that Vaidev left City K:
2 h 30 min before 1.00 p.m. = 10.30 a.m.

(b)
Remaining distance that they had to cover to reach City L
= 300 - 180
= 120 km

Duration that Vaidev had to travel before reaching City L
= 120 ÷ 72
= 1²₃ h

Duration that Ahmad had to travel before reaching City L
= 120 ÷ 60
= 2 h

Duration that Ahmad took to arrive later than Vaidev in City L
= 2 - 1²₃
= ¹₃ h

Answer(s): (a) 10.30 a.m.; (b) ¹₃ h