City L and City M is 300 km apart. Gabriel left City L for City M at 7.00 a.m. travelling at an average speed of 60 km/h. Lee left City L later than Gabriel and caught up with him at 10.00 a.m. Lee was travelling at a speed of 80 km/h.

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

(a)
From 7.00 a.m. to 10.00 a.m. = 3 h

Distance that Gabriel covered when Lee caught up with Gabriel
= 3 x 60
= 180 km

Time that Lee took to travel 180 km
= 180 ÷ 80
= 2¹₄ h

1 h = 60 min
¹₄ h = ¹₄ x 60 = 15 min
2¹₄ h = 2 h 15 min

Time that Lee left City L:
2 h 15 min before 10.00 a.m. = 7.45 a.m.

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

Duration that Lee had to travel before reaching City M
= 120 ÷ 80
= 1¹₂ h

Duration that Gabriel had to travel before reaching City M
= 120 ÷ 60
= 2 h

Duration that Gabriel took to arrive later than Lee in City M
= 2 - 1¹₂
= ¹₂ h

Answer(s): (a) 7.45 a.m.; (b) ¹₂ h