City S and City T are 459 km apart. At 6.12 p.m., Will is travelling at a uniform speed left City S for City T while Seth set off from City T to City S along the same road at a uniform speed, which was 9 km/h slower than that of Will. The two met at 9.12 p.m.
- Find the speed of Will.
- If Seth 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 Will and Seth to travel from 6.12 p.m. to 9.12 p.m. = 3 h
Average speed of Will and Seth
= 459 ÷ 3
= 153 km/h
Will's speed
= (153 + 9) ÷ 2
= 162 ÷ 2
= 81 km/h
(b)
Seth's speed
= 81 - 9
= 72 km/h
Distance that Seth travelled in 3 h
= 3 x 72
= 216 km
Remaining distance that Seth needed to travel
= 459 - 216
= 243 km
Time that Seth needed to reach his destination after the two met
= 243 ÷ 72
= 3
2772 = 3
38 h
Answer(s): (a) 81 km/h; (b) 3
38 h