City S and City T is 350 km apart. Japheth left City S for City T at 9.00 a.m. travelling at an average speed of 70 km/h. Luis left City S later than Japheth and caught up with him at 11.00 a.m. Luis was travelling at a speed of 80 km/h.

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

Time that Luis 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 Luis 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
= 350 - 140
= 210 km

Duration that Luis had to travel before reaching City T
= 210 ÷ 80
= 2⁵₈ h

Duration that Japheth had to travel before reaching City T
= 210 ÷ 70
= 3 h

Duration that Japheth took to arrive later than Luis in City T
= 3 - 2⁵₈
= ³₈ h

Answer(s): (a) 9.15 a.m.; (b) ³₈ h