City D and City E are 408 km apart. At 2.57 p.m., Ahmad is travelling at a uniform speed left City D for City E while Zane set off from City E to City D along the same road at a uniform speed, which was 12 km/h slower than that of Ahmad. The two met at 4.57 p.m.
- Find the speed of Ahmad.
- If Zane 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 Ahmad and Zane to travel from 2.57 p.m. to 4.57 p.m. = 2 h
Average speed of Ahmad and Zane
= 408 ÷ 2
= 204 km/h
Ahmad's speed
= (204 + 12) ÷ 2
= 216 ÷ 2
= 108 km/h
(b)
Zane's speed
= 108 - 12
= 96 km/h
Distance that Zane travelled in 2 h
= 2 x 96
= 192 km
Remaining distance that Zane needed to travel
= 408 - 192
= 216 km
Time that Zane needed to reach his destination after the two met
= 216 ÷ 96
= 2
2496 = 2
14 h
Answer(s): (a) 108 km/h; (b) 2
14 h