City E and City F are 432 km apart. At 5.41 p.m., David is travelling at a uniform speed left City E for City F while Owen set off from City F to City E along the same road at a uniform speed, which was 12 km/h slower than that of David. The two met at 8.41 p.m.
- Find the speed of David.
- If Owen 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 David and Owen to travel from 5.41 p.m. to 8.41 p.m. = 3 h
Average speed of David and Owen
= 432 ÷ 3
= 144 km/h
David's speed
= (144 + 12) ÷ 2
= 156 ÷ 2
= 78 km/h
(b)
Owen's speed
= 78 - 12
= 66 km/h
Distance that Owen travelled in 3 h
= 3 x 66
= 198 km
Remaining distance that Owen needed to travel
= 432 - 198
= 234 km
Time that Owen needed to reach his destination after the two met
= 234 ÷ 66
= 3
3666 = 3
611 h
Answer(s): (a) 78 km/h; (b) 3
611 h