City F and City G is 420 km apart. Wesley left City F for City G at 8.00 a.m. travelling at an average speed of 60 km/h. Bryan left City F later than Wesley and caught up with him at 10.00 a.m. Bryan was travelling at a speed of 90 km/h.

1. At what time did Bryan leave City F?
2. How much later did Wesley arrive in City G than Bryan? 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 Wesley covered when Bryan caught up with Wesley
= 2 x 60
= 120 km

Time that Bryan took to travel 120 km
= 120 ÷ 90
= 1¹₃ h

1 h = 60 min
¹₃ h = ¹₃ x 60 = 20 min
1¹₃ h = 1 h 20 min

Time that Bryan left City F:
1 h 20 min before 10.00 a.m. = 8.40 a.m.

(b)
Remaining distance that they had to cover to reach City G
= 420 - 120
= 300 km

Duration that Bryan had to travel before reaching City G
= 300 ÷ 90
= 3¹₃ h

Duration that Wesley had to travel before reaching City G
= 300 ÷ 60
= 5 h

Duration that Wesley took to arrive later than Bryan in City G
= 5 - 3¹₃
= 1²₃ h

Answer(s): (a) 8.40 a.m.; (b) 1²₃ h