City J and City K are 324 km apart. At 4.14 p.m., Sean is travelling at a uniform speed left City J for City K while Archie set off from City K to City J along the same road at a uniform speed, which was 6 km/h slower than that of Sean. The two met at 6.14 p.m.
- Find the speed of Sean.
- If Archie 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 Sean and Archie to travel from 4.14 p.m. to 6.14 p.m. = 2 h
Average speed of Sean and Archie
= 324 ÷ 2
= 162 km/h
Sean's speed
= (162 + 6) ÷ 2
= 168 ÷ 2
= 84 km/h
(b)
Archie's speed
= 84 - 6
= 78 km/h
Distance that Archie travelled in 2 h
= 2 x 78
= 156 km
Remaining distance that Archie needed to travel
= 324 - 156
= 168 km
Time that Archie needed to reach his destination after the two met
= 168 ÷ 78
= 2
1278 = 2
213 h
Answer(s): (a) 84 km/h; (b) 2
213 h