City C and City D are 540 km apart. At 5.54 p.m., Lee is travelling at a uniform speed left City C for City D while Ken set off from City D to City C along the same road at a uniform speed, which was 5 km/h slower than that of Lee. The two met at 9.54 p.m.
- Find the speed of Lee.
- If Ken 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 Ken to travel from 5.54 p.m. to 9.54 p.m. = 4 h
Average speed of Lee and Ken
= 540 ÷ 4
= 135 km/h
Lee's speed
= (135 + 5) ÷ 2
= 140 ÷ 2
= 70 km/h
(b)
Ken's speed
= 70 - 5
= 65 km/h
Distance that Ken travelled in 4 h
= 4 x 65
= 260 km
Remaining distance that Ken needed to travel
= 540 - 260
= 280 km
Time that Ken needed to reach his destination after the two met
= 280 ÷ 65
= 4
2065 = 4
413 h
Answer(s): (a) 70 km/h; (b) 4
413 h