Tommy drove from Town P to Town Q which was 640 km away. He started from Town P at an average speed of 64 km/h. He maintained this speed for 4 h before increasing it by 8 km/h for the rest of the journey to Town Q.
- How long did he take to complete the whole journey?
- What was his average speed from Town P to Town Q?
(a)
Distance of 1st part of the journey
= 4 x 64
= 256 km
New speed for rest of the journey
= 64 + 8
= 72 km / h
Remaining distance for rest of the journey
= 640 - 256
= 384 km
Time taken for rest of the journey
= 384 ÷ 72
= 4 h
Total time taken
= 4 + 4
= 8 h
(b)
Average speed of the whole journey
= 640 ÷ 8
= 80 km
Answer(s): (a) 8 h; (b) 80km/h