City H and City J are 411 km apart. At 5.40 p.m., Sean is travelling at a uniform speed left City H for City J while Bryan set off from City J to City H along the same road at a uniform speed, which was 11 km/h slower than that of Sean. The two met at 8.40 p.m.
- Find the speed of Sean.
- If Bryan 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 Bryan to travel from 5.40 p.m. to 8.40 p.m. = 3 h
Average speed of Sean and Bryan
= 411 ÷ 3
= 137 km/h
Sean's speed
= (137 + 11) ÷ 2
= 148 ÷ 2
= 74 km/h
(b)
Bryan's speed
= 74 - 11
= 63 km/h
Distance that Bryan travelled in 3 h
= 3 x 63
= 189 km
Remaining distance that Bryan needed to travel
= 411 - 189
= 222 km
Time that Bryan needed to reach his destination after the two met
= 222 ÷ 63
= 3
3363 = 3
1121 h
Answer(s): (a) 74 km/h; (b) 3
1121 h