City F and City G is 490 km apart. Harry left City F for City G at 8.00 a.m. travelling at an average speed of 70 km/h. Vaidev left City F later than Harry and caught up with him at 11.00 a.m. Vaidev was travelling at a speed of 84 km/h.

1. At what time did Vaidev leave City F?
2. How much later did Harry arrive in City G than Vaidev? Express your answer in h as a fraction or mixed number.

(a)
From 8.00 a.m. to 11.00 a.m. = 3 h

Distance that Harry covered when Vaidev caught up with Harry
= 3 x 70
= 210 km

Time that Vaidev took to travel 210 km
= 210 ÷ 84
= 2¹₂ h

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

Time that Vaidev left City F:
2 h 30 min before 11.00 a.m. = 8.30 a.m.

(b)
Remaining distance that they had to cover to reach City G
= 490 - 210
= 280 km

Duration that Vaidev had to travel before reaching City G
= 280 ÷ 84
= 3¹₃ h

Duration that Harry had to travel before reaching City G
= 280 ÷ 70
= 4 h

Duration that Harry took to arrive later than Vaidev in City G
= 4 - 3¹₃
= ²₃ h

Answer(s): (a) 8.30 a.m.; (b) ²₃ h