City V and City W are 450 km apart. At 4.54 p.m., Riordan is travelling at a uniform speed left City V for City W while Daniel set off from City W to City V along the same road at a uniform speed, which was 9 km/h slower than that of Riordan. The two met at 6.54 p.m.
- Find the speed of Riordan.
- 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 Riordan and Daniel to travel from 4.54 p.m. to 6.54 p.m. = 2 h
Average speed of Riordan and Daniel
= 450 ÷ 2
= 225 km/h
Riordan's speed
= (225 + 9) ÷ 2
= 234 ÷ 2
= 117 km/h
(b)
Daniel's speed
= 117 - 9
= 108 km/h
Distance that Daniel travelled in 2 h
= 2 x 108
= 216 km
Remaining distance that Daniel needed to travel
= 450 - 216
= 234 km
Time that Daniel needed to reach his destination after the two met
= 234 ÷ 108
= 2
18108 = 2
16 h
Answer(s): (a) 117 km/h; (b) 2
16 h