City Z and City A are 492 km apart. At 6.15 p.m., Zeph is travelling at a uniform speed left City Z for City A while Seth set off from City A to City Z along the same road at a uniform speed, which was 8 km/h slower than that of Zeph. The two met at 9.15 p.m.
- Find the speed of Zeph.
- If Seth 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 Zeph and Seth to travel from 6.15 p.m. to 9.15 p.m. = 3 h
Average speed of Zeph and Seth
= 492 ÷ 3
= 164 km/h
Zeph's speed
= (164 + 8) ÷ 2
= 172 ÷ 2
= 86 km/h
(b)
Seth's speed
= 86 - 8
= 78 km/h
Distance that Seth travelled in 3 h
= 3 x 78
= 234 km
Remaining distance that Seth needed to travel
= 492 - 234
= 258 km
Time that Seth needed to reach his destination after the two met
= 258 ÷ 78
= 3
2478 = 3
413 h
Answer(s): (a) 86 km/h; (b) 3
413 h