City W and City X are 429 km apart. At 5.38 p.m., Flynn is travelling at a uniform speed left City W for City X while Zeph set off from City X to City W along the same road at a uniform speed, which was 11 km/h slower than that of Flynn. The two met at 8.38 p.m.

1. Find the speed of Flynn.
2. If Zeph continued to travel at the same speed, how long would it take for him to reach his destination after the two met? Express your answer in mixed number.

(a)
Time taken for Flynn and Zeph to travel from 5.38 p.m. to 8.38 p.m. = 3 h

Average speed of Flynn and Zeph
= 429 ÷ 3
= 143 km/h

Flynn's speed
= (143 + 11) ÷ 2
= 154 ÷ 2 
= 77 km/h

(b)
Zeph's speed
= 77 - 11
= 66 km/h

Distance that Zeph travelled in 3 h
= 3 x 66
= 198 km

Remaining distance that Zeph needed to travel
= 429 - 198
= 231 km

Time that Zeph needed to reach his destination after the two met
= 231 ÷ 66
= 3³³₆₆
= 3¹₂ h

Answer(s): (a) 77 km/h; (b) 3¹₂ h