City B and City C are 580 km apart. At 3.15 p.m., Zeph is travelling at a uniform speed left City B for City C while Flynn set off from City C to City B along the same road at a uniform speed, which was 9 km/h slower than that of Zeph. The two met at 7.15 p.m.
- Find the speed of Zeph.
- If Flynn 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 Zeph and Flynn to travel from 3.15 p.m. to 7.15 p.m. = 4 h
Average speed of Zeph and Flynn
= 580 ÷ 4
= 145 km/h
Zeph's speed
= (145 + 9) ÷ 2
= 154 ÷ 2
= 77 km/h
(b)
Flynn's speed
= 77 - 9
= 68 km/h
Distance that Flynn travelled in 4 h
= 4 x 68
= 272 km
Remaining distance that Flynn needed to travel
= 580 - 272
= 308 km
Time that Flynn needed to reach his destination after the two met
= 308 ÷ 68
= 4
3668 = 4
917 h
Answer(s): (a) 77 km/h; (b) 4
917 h