Charlie drove from Town N to Town P which was 640 km away. He started from Town N at an average speed of 60 km/h. He maintained this speed for 2 h before increasing it by 5 km/h for the rest of the journey to Town P.
- How long did he take to complete the whole journey?
- What was his average speed from Town N to Town P?
(a)
Distance of 1st part of the journey
= 2 x 60
= 120 km
New speed for rest of the journey
= 60 + 5
= 65 km / h
Remaining distance for rest of the journey
= 640 - 120
= 520 km
Time taken for rest of the journey
= 520 ÷ 65
= 6 h
Total time taken
= 2 + 6
= 8 h
(b)
Average speed of the whole journey
= 640 ÷ 8
= 80 km
Answer(s): (a) 8 h; (b) 80km/h