City Y and City Z are 456 km apart. At 4.21 p.m., Zeph is travelling at a uniform speed left City Y for City Z while Ian set off from City Z to City Y along the same road at a uniform speed, which was 10 km/h slower than that of Zeph. The two met at 8.21 p.m.
- Find the speed of Zeph.
- If Ian 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 Zeph and Ian to travel from 4.21 p.m. to 8.21 p.m. = 4 h
Average speed of Zeph and Ian
= 456 ÷ 4
= 114 km/h
Zeph's speed
= (114 + 10) ÷ 2
= 124 ÷ 2
= 62 km/h
(b)
Ian's speed
= 62 - 10
= 52 km/h
Distance that Ian travelled in 4 h
= 4 x 52
= 208 km
Remaining distance that Ian needed to travel
= 456 - 208
= 248 km
Time that Ian needed to reach his destination after the two met
= 248 ÷ 52
= 4
4052 = 4
1013 h
Answer(s): (a) 62 km/h; (b) 4
1013 h