City Z and City A are 432 km apart. At 6.22 p.m., Oliver is travelling at a uniform speed left City Z for City A while Ahmad 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 Oliver. The two met at 9.22 p.m.
- Find the speed of Oliver.
- If Ahmad 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 Oliver and Ahmad to travel from 6.22 p.m. to 9.22 p.m. = 3 h
Average speed of Oliver and Ahmad
= 432 ÷ 3
= 144 km/h
Oliver's speed
= (144 + 8) ÷ 2
= 152 ÷ 2
= 76 km/h
(b)
Ahmad's speed
= 76 - 8
= 68 km/h
Distance that Ahmad travelled in 3 h
= 3 x 68
= 204 km
Remaining distance that Ahmad needed to travel
= 432 - 204
= 228 km
Time that Ahmad needed to reach his destination after the two met
= 228 ÷ 68
= 3
2468 = 3
617 h
Answer(s): (a) 76 km/h; (b) 3
617 h