City U and City V are 400 km apart. At 5.20 p.m., Warren is travelling at a uniform speed left City U for City V while Archie set off from City V to City U along the same road at a uniform speed, which was 8 km/h slower than that of Warren. The two met at 7.20 p.m.
- Find the speed of Warren.
- 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 Warren and Archie to travel from 5.20 p.m. to 7.20 p.m. = 2 h
Average speed of Warren and Archie
= 400 ÷ 2
= 200 km/h
Warren's speed
= (200 + 8) ÷ 2
= 208 ÷ 2
= 104 km/h
(b)
Archie's speed
= 104 - 8
= 96 km/h
Distance that Archie travelled in 2 h
= 2 x 96
= 192 km
Remaining distance that Archie needed to travel
= 400 - 192
= 208 km
Time that Archie needed to reach his destination after the two met
= 208 ÷ 96
= 2
1696 = 2
16 h
Answer(s): (a) 104 km/h; (b) 2
16 h