City D and City E are 316 km apart. At 4.21 p.m., Japheth is travelling at a uniform speed left City D for City E while Vincent set off from City E to City D along the same road at a uniform speed, which was 6 km/h slower than that of Japheth. The two met at 6.21 p.m.
- Find the speed of Japheth.
- If Vincent 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 Japheth and Vincent to travel from 4.21 p.m. to 6.21 p.m. = 2 h
Average speed of Japheth and Vincent
= 316 ÷ 2
= 158 km/h
Japheth's speed
= (158 + 6) ÷ 2
= 164 ÷ 2
= 82 km/h
(b)
Vincent's speed
= 82 - 6
= 76 km/h
Distance that Vincent travelled in 2 h
= 2 x 76
= 152 km
Remaining distance that Vincent needed to travel
= 316 - 152
= 164 km
Time that Vincent needed to reach his destination after the two met
= 164 ÷ 76
= 2
1276 = 2
319 h
Answer(s): (a) 82 km/h; (b) 2
319 h