City U and City V are 342 km apart. At 4.23 p.m., Oliver is travelling at a uniform speed left City U for City V while Daniel set off from City V to City U along the same road at a uniform speed, which was 9 km/h slower than that of Oliver. The two met at 6.23 p.m.
- Find the speed of Oliver.
- If Daniel 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 Daniel to travel from 4.23 p.m. to 6.23 p.m. = 2 h
Average speed of Oliver and Daniel
= 342 ÷ 2
= 171 km/h
Oliver's speed
= (171 + 9) ÷ 2
= 180 ÷ 2
= 90 km/h
(b)
Daniel's speed
= 90 - 9
= 81 km/h
Distance that Daniel travelled in 2 h
= 2 x 81
= 162 km
Remaining distance that Daniel needed to travel
= 342 - 162
= 180 km
Time that Daniel needed to reach his destination after the two met
= 180 ÷ 81
= 2
1881 = 2
29 h
Answer(s): (a) 90 km/h; (b) 2
29 h