Shiyun left home at 10.40 a.m. and drove towards the city which was 648 km away. For the first 316 km, she was travelling at 79 km/h. Then she increased her speed by 4 km/h and completed the remaining journey.
- How long did she take for her whole journey?
- At what time did she reach the city?
(a)
Time taken to travel 316 km
= 316 ÷ 79
= 4 h
Distance of the remaining journey
= 648 - 316
= 332 km
Speed for remaining journey
= 79 + 4
= 83 km/h
Time taken to travel remaining journey
= 332 ÷ 83
= 4 h
Time taken to travel the whole journey
= 4 + 4
= 8 h
(b)
8 h after 10.40 a.m. = 6.40 p.m.
Answer(s): (a) 8 h; (b) 6.40 p.m.