City B and City C are 418 km apart. At 5.13 p.m., Valen is travelling at a uniform speed left City B for City C while David set off from City C to City B along the same road at a uniform speed, which was 11 km/h slower than that of Valen. The two met at 7.13 p.m.
- Find the speed of Valen.
- If David 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 Valen and David to travel from 5.13 p.m. to 7.13 p.m. = 2 h
Average speed of Valen and David
= 418 ÷ 2
= 209 km/h
Valen's speed
= (209 + 11) ÷ 2
= 220 ÷ 2
= 110 km/h
(b)
David's speed
= 110 - 11
= 99 km/h
Distance that David travelled in 2 h
= 2 x 99
= 198 km
Remaining distance that David needed to travel
= 418 - 198
= 220 km
Time that David needed to reach his destination after the two met
= 220 ÷ 99
= 2
2299 = 2
29 h
Answer(s): (a) 110 km/h; (b) 2
29 h