Barbara left home at 7.40 a.m. and drove towards the airport which was 812 km away. For the first 432 km, she was travelling at 72 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 airport?
(a)
Time taken to travel 432 km
= 432 ÷ 72
= 6 h
Distance of the remaining journey
= 812 - 432
= 380 km
Speed for remaining journey
= 72 + 4
= 76 km/h
Time taken to travel remaining journey
= 380 ÷ 76
= 5 h
Time taken to travel the whole journey
= 5 + 6
= 11 h
(b)
11 h after 7.40 a.m. = 6.40 p.m.
Answer(s): (a) 11 h; (b) 6.40 p.m.