City Z and City A are 486 km apart. At 6.24 p.m., Japheth is travelling at a uniform speed left City Z for City A while Charlie set off from City A to City Z along the same road at a uniform speed, which was 6 km/h slower than that of Japheth. The two met at 9.24 p.m.
- Find the speed of Japheth.
- If Charlie 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 Charlie to travel from 6.24 p.m. to 9.24 p.m. = 3 h
Average speed of Japheth and Charlie
= 486 ÷ 3
= 162 km/h
Japheth's speed
= (162 + 6) ÷ 2
= 168 ÷ 2
= 84 km/h
(b)
Charlie's speed
= 84 - 6
= 78 km/h
Distance that Charlie travelled in 3 h
= 3 x 78
= 234 km
Remaining distance that Charlie needed to travel
= 486 - 234
= 252 km
Time that Charlie needed to reach his destination after the two met
= 252 ÷ 78
= 3
1878 = 3
313 h
Answer(s): (a) 84 km/h; (b) 3
313 h