City A and City B are 540 km apart. At 1.39 p.m., Daniel is travelling at a uniform speed left City A for City B while Ivan set off from City B to City A along the same road at a uniform speed, which was 5 km/h slower than that of Daniel. The two met at 5.39 p.m.
- Find the speed of Daniel.
- If Ivan 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 Daniel and Ivan to travel from 1.39 p.m. to 5.39 p.m. = 4 h
Average speed of Daniel and Ivan
= 540 ÷ 4
= 135 km/h
Daniel's speed
= (135 + 5) ÷ 2
= 140 ÷ 2
= 70 km/h
(b)
Ivan's speed
= 70 - 5
= 65 km/h
Distance that Ivan travelled in 4 h
= 4 x 65
= 260 km
Remaining distance that Ivan needed to travel
= 540 - 260
= 280 km
Time that Ivan needed to reach his destination after the two met
= 280 ÷ 65
= 4
2065 = 4
413 h
Answer(s): (a) 70 km/h; (b) 4
413 h