City G and City H are 564 km apart. At 5.36 p.m., Oscar is travelling at a uniform speed left City G for City H while Fred set off from City H to City G along the same road at a uniform speed, which was 5 km/h slower than that of Oscar. The two met at 9.36 p.m.
- Find the speed of Oscar.
- If Fred 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 Oscar and Fred to travel from 5.36 p.m. to 9.36 p.m. = 4 h
Average speed of Oscar and Fred
= 564 ÷ 4
= 141 km/h
Oscar's speed
= (141 + 5) ÷ 2
= 146 ÷ 2
= 73 km/h
(b)
Fred's speed
= 73 - 5
= 68 km/h
Distance that Fred travelled in 4 h
= 4 x 68
= 272 km
Remaining distance that Fred needed to travel
= 564 - 272
= 292 km
Time that Fred needed to reach his destination after the two met
= 292 ÷ 68
= 4
2068 = 4
517 h
Answer(s): (a) 73 km/h; (b) 4
517 h