City S and City T is 490 km apart. Flynn left City S for City T at 9.00 a.m. travelling at an average speed of 70 km/h. Ryan left City S later than Flynn and caught up with him at 11.00 a.m. Ryan was travelling at a speed of 80 km/h.

1. At what time did Ryan leave City S?
2. How much later did Flynn arrive in City T than Ryan? 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 Flynn covered when Ryan caught up with Flynn
= 2 x 70
= 140 km

Time that Ryan took to travel 140 km
= 140 ÷ 80
= 1³₄ h

1 h = 60 min
³₄ h = ³₄ x 60 = 45 min
1³₄ h = 1 h 45 min

Time that Ryan left City S:
1 h 45 min before 11.00 a.m. = 9.15 a.m.

(b)
Remaining distance that they had to cover to reach City T
= 490 - 140
= 350 km

Duration that Ryan had to travel before reaching City T
= 350 ÷ 80
= 4³₈ h

Duration that Flynn had to travel before reaching City T
= 350 ÷ 70
= 5 h

Duration that Flynn took to arrive later than Ryan in City T
= 5 - 4³₈
= ⁵₈ h

Answer(s): (a) 9.15 a.m.; (b) ⁵₈ h