City G and City H are 342 km apart. At 2.40 p.m., Brandon is travelling at a uniform speed left City G for City H while Harry set off from City H to City G along the same road at a uniform speed, which was 9 km/h slower than that of Brandon. The two met at 4.40 p.m.
- Find the speed of Brandon.
- If Harry 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 Brandon and Harry to travel from 2.40 p.m. to 4.40 p.m. = 2 h
Average speed of Brandon and Harry
= 342 ÷ 2
= 171 km/h
Brandon's speed
= (171 + 9) ÷ 2
= 180 ÷ 2
= 90 km/h
(b)
Harry's speed
= 90 - 9
= 81 km/h
Distance that Harry travelled in 2 h
= 2 x 81
= 162 km
Remaining distance that Harry needed to travel
= 342 - 162
= 180 km
Time that Harry needed to reach his destination after the two met
= 180 ÷ 81
= 2
1881 = 2
29 h
Answer(s): (a) 90 km/h; (b) 2
29 h