City L and City M is 468 km apart. Bryan left City L for City M at 9.00 a.m. travelling at an average speed of 78 km/h. Tommy left City L later than Bryan and caught up with him at 11.00 a.m. Tommy was travelling at a speed of 104 km/h.

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

(a)
From 9.00 a.m. to 11.00 a.m. = 2 h

Distance that Bryan covered when Tommy caught up with Bryan
= 2 x 78
= 156 km

Time that Tommy took to travel 156 km
= 156 ÷ 104
= 1¹₂ h

1 h = 60 min
¹₂ h = ¹₂ x 60 = 30 min
1¹₂ h = 1 h 30 min

Time that Tommy left City L:
1 h 30 min before 11.00 a.m. = 9.30 a.m.

(b)
Remaining distance that they had to cover to reach City M
= 468 - 156
= 312 km

Duration that Tommy had to travel before reaching City M
= 312 ÷ 104
= 3 h

Duration that Bryan had to travel before reaching City M
= 312 ÷ 78
= 4 h

Duration that Bryan took to arrive later than Tommy in City M
= 4 - 3
= 1 h

Answer(s): (a) 9.30 a.m.; (b) 1 h