City N and City P are 512 km apart. At 4.50 p.m., Ian is travelling at a uniform speed left City N for City P while Neave set off from City P to City N along the same road at a uniform speed, which was 8 km/h slower than that of Ian. The two met at 8.50 p.m.
- Find the speed of Ian.
- If Neave 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 Ian and Neave to travel from 4.50 p.m. to 8.50 p.m. = 4 h
Average speed of Ian and Neave
= 512 ÷ 4
= 128 km/h
Ian's speed
= (128 + 8) ÷ 2
= 136 ÷ 2
= 68 km/h
(b)
Neave's speed
= 68 - 8
= 60 km/h
Distance that Neave travelled in 4 h
= 4 x 60
= 240 km
Remaining distance that Neave needed to travel
= 512 - 240
= 272 km
Time that Neave needed to reach his destination after the two met
= 272 ÷ 60
= 4
3260 = 4
815 h
Answer(s): (a) 68 km/h; (b) 4
815 h