City W and City X is 476 km apart. Eric left City W for City X at 11.00 a.m. travelling at an average speed of 68 km/h. Mark left City W later than Eric and caught up with him at 1.00 p.m. Mark was travelling at a speed of 96 km/h.

1. At what time did Mark leave City W?
2. How much later did Eric arrive in City X than Mark? 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 Eric covered when Mark caught up with Eric
= 2 x 68
= 136 km

Time that Mark took to travel 136 km
= 136 ÷ 96
= 1⁵₁₂ h

1 h = 60 min
⁵₁₂ h = ⁵₁₂ x 60 = 25 min
1⁵₁₂ h = 1 h 25 min

Time that Mark left City W:
1 h 25 min before 1.00 p.m. = 11.35 a.m.

(b)
Remaining distance that they had to cover to reach City X
= 476 - 136
= 340 km

Duration that Mark had to travel before reaching City X
= 340 ÷ 96
= 3¹³₂₄ h

Duration that Eric had to travel before reaching City X
= 340 ÷ 68
= 5 h

Duration that Eric took to arrive later than Mark in City X
= 5 - 3¹³₂₄
= 1¹¹₂₄ h

Answer(s): (a) 11.35 a.m.; (b) 1¹¹₂₄ h