City H and City J is 350 km apart. Seth left City H for City J at 11.00 a.m. travelling at an average speed of 70 km/h. Eric left City H later than Seth and caught up with him at 1.00 p.m. Eric was travelling at a speed of 84 km/h.

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

(a)
From 11.00 a.m. to 1.00 p.m. = 2 h

Distance that Seth covered when Eric caught up with Seth
= 2 x 70
= 140 km

Time that Eric took to travel 140 km
= 140 ÷ 84
= 1²₃ h

1 h = 60 min
²₃ h = ²₃ x 60 = 40 min
1²₃ h = 1 h 40 min

Time that Eric left City H:
1 h 40 min before 1.00 p.m. = 11.20 a.m.

(b)
Remaining distance that they had to cover to reach City J
= 350 - 140
= 210 km

Duration that Eric had to travel before reaching City J
= 210 ÷ 84
= 2¹₂ h

Duration that Seth had to travel before reaching City J
= 210 ÷ 70
= 3 h

Duration that Seth took to arrive later than Eric in City J
= 3 - 2¹₂
= ¹₂ h

Answer(s): (a) 11.20 a.m.; (b) ¹₂ h