City S and City T are 393 km apart. At 6.52 p.m., Luis is travelling at a uniform speed left City S for City T while Paul set off from City T to City S along the same road at a uniform speed, which was 11 km/h slower than that of Luis. The two met at 9.52 p.m.

1. Find the speed of Luis.
2. If Paul 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 Luis and Paul to travel from 6.52 p.m. to 9.52 p.m. = 3 h

Average speed of Luis and Paul
= 393 ÷ 3
= 131 km/h

Luis's speed
= (131 + 11) ÷ 2
= 142 ÷ 2 
= 71 km/h

(b)
Paul's speed
= 71 - 11
= 60 km/h

Distance that Paul travelled in 3 h
= 3 x 60
= 180 km

Remaining distance that Paul needed to travel
= 393 - 180
= 213 km

Time that Paul needed to reach his destination after the two met
= 213 ÷ 60
= 3³³₆₀
= 3¹¹₂₀ h

Answer(s): (a) 71 km/h; (b) 3¹¹₂₀ h