City L and City M are 420 km apart. At 2.10 p.m., Jenson is travelling at a uniform speed left City L for City M while Simon set off from City M to City L along the same road at a uniform speed, which was 10 km/h slower than that of Jenson. The two met at 5.10 p.m.
- Find the speed of Jenson.
- If Simon 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 Jenson and Simon to travel from 2.10 p.m. to 5.10 p.m. = 3 h
Average speed of Jenson and Simon
= 420 ÷ 3
= 140 km/h
Jenson's speed
= (140 + 10) ÷ 2
= 150 ÷ 2
= 75 km/h
(b)
Simon's speed
= 75 - 10
= 65 km/h
Distance that Simon travelled in 3 h
= 3 x 65
= 195 km
Remaining distance that Simon needed to travel
= 420 - 195
= 225 km
Time that Simon needed to reach his destination after the two met
= 225 ÷ 65
= 3
3065 = 3
613 h
Answer(s): (a) 75 km/h; (b) 3
613 h