City Q and City R are 380 km apart. At 2.19 p.m., Lee is travelling at a uniform speed left City Q for City R while Ben set off from City R to City Q along the same road at a uniform speed, which was 10 km/h slower than that of Lee. The two met at 4.19 p.m.

1. Find the speed of Lee.
2. If Ben 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 Lee and Ben to travel from 2.19 p.m. to 4.19 p.m. = 2 h

Average speed of Lee and Ben
= 380 ÷ 2
= 190 km/h

Lee's speed
= (190 + 10) ÷ 2
= 200 ÷ 2 
= 100 km/h

(b)
Ben's speed
= 100 - 10
= 90 km/h

Distance that Ben travelled in 2 h
= 2 x 90
= 180 km

Remaining distance that Ben needed to travel
= 380 - 180
= 200 km

Time that Ben needed to reach his destination after the two met
= 200 ÷ 90
= 2²⁰₉₀
= 2²₉ h

Answer(s): (a) 100 km/h; (b) 2²₉ h