City G and City H is 360 km apart. Billy left City G for City H at 11.00 a.m. travelling at an average speed of 60 km/h. Archie left City G later than Billy and caught up with him at 2.00 p.m. Archie was travelling at a speed of 80 km/h.

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

(a)
From 11.00 a.m. to 2.00 p.m. = 3 h

Distance that Billy covered when Archie caught up with Billy
= 3 x 60
= 180 km

Time that Archie 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 Archie left City G:
2 h 15 min before 2.00 p.m. = 11.45 a.m.

(b)
Remaining distance that they had to cover to reach City H
= 360 - 180
= 180 km

Duration that Archie had to travel before reaching City H
= 180 ÷ 80
= 2¹₄ h

Duration that Billy had to travel before reaching City H
= 180 ÷ 60
= 3 h

Duration that Billy took to arrive later than Archie in City H
= 3 - 2¹₄
= ³₄ h

Answer(s): (a) 11.45 a.m.; (b) ³₄ h