Dylan drove from Town U to Town V which was 400 km away. He started from Town U at an average speed of 72 km/h. He maintained this speed for 4 h before increasing it by 6 km/h for the rest of the journey to Town V.
- How long did he take to complete the whole journey?
- What was his average speed from Town U to Town V?
(a)
Distance of 1st part of the journey
= 4 x 72
= 288 km
New speed for rest of the journey
= 72 + 6
= 78 km / h
Remaining distance for rest of the journey
= 400 - 288
= 112 km
Time taken for rest of the journey
= 112 ÷ 78
= 1 h
Total time taken
= 4 + 1
= 5 h
(b)
Average speed of the whole journey
= 400 ÷ 5
= 80 km
Answer(s): (a) 5 h; (b) 80km/h