City Q and City R is 455 km apart. Harry left City Q for City R at 8.00 a.m. travelling at an average speed of 65 km/h. Bobby left City Q later than Harry and caught up with him at 10.00 a.m. Bobby was travelling at a speed of 104 km/h.

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

(a)
From 8.00 a.m. to 10.00 a.m. = 2 h

Distance that Harry covered when Bobby caught up with Harry
= 2 x 65
= 130 km

Time that Bobby took to travel 130 km
= 130 ÷ 104
= 1¹₄ h

1 h = 60 min
¹₄ h = ¹₄ x 60 = 15 min
1¹₄ h = 1 h 15 min

Time that Bobby left City Q:
1 h 15 min before 10.00 a.m. = 8.45 a.m.

(b)
Remaining distance that they had to cover to reach City R
= 455 - 130
= 325 km

Duration that Bobby had to travel before reaching City R
= 325 ÷ 104
= 3¹₈ h

Duration that Harry had to travel before reaching City R
= 325 ÷ 65
= 5 h

Duration that Harry took to arrive later than Bobby in City R
= 5 - 3¹₈
= 1⁷₈ h

Answer(s): (a) 8.45 a.m.; (b) 1⁷₈ h