City W and City X are 420 km apart. At 4.47 p.m., Ryan is travelling at a uniform speed left City W for City X while Cole set off from City X to City W along the same road at a uniform speed, which was 8 km/h slower than that of Ryan. The two met at 7.47 p.m.
- Find the speed of Ryan.
- If Cole 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 Ryan and Cole to travel from 4.47 p.m. to 7.47 p.m. = 3 h
Average speed of Ryan and Cole
= 420 ÷ 3
= 140 km/h
Ryan's speed
= (140 + 8) ÷ 2
= 148 ÷ 2
= 74 km/h
(b)
Cole's speed
= 74 - 8
= 66 km/h
Distance that Cole travelled in 3 h
= 3 x 66
= 198 km
Remaining distance that Cole needed to travel
= 420 - 198
= 222 km
Time that Cole needed to reach his destination after the two met
= 222 ÷ 66
= 3
2466 = 3
411 h
Answer(s): (a) 74 km/h; (b) 3
411 h