City T and City U are 462 km apart. At 3.10 p.m., Bryan is travelling at a uniform speed left City T for City U while David set off from City U to City T along the same road at a uniform speed, which was 10 km/h slower than that of Bryan. The two met at 6.10 p.m.
- Find the speed of Bryan.
- 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 Bryan and David to travel from 3.10 p.m. to 6.10 p.m. = 3 h
Average speed of Bryan and David
= 462 ÷ 3
= 154 km/h
Bryan's speed
= (154 + 10) ÷ 2
= 164 ÷ 2
= 82 km/h
(b)
David's speed
= 82 - 10
= 72 km/h
Distance that David travelled in 3 h
= 3 x 72
= 216 km
Remaining distance that David needed to travel
= 462 - 216
= 246 km
Time that David needed to reach his destination after the two met
= 246 ÷ 72
= 3
3072 = 3
512 h
Answer(s): (a) 82 km/h; (b) 3
512 h