Mark drove from Town H to Town J which was 712 km away. He started from Town H at an average speed of 73 km/h. He maintained this speed for 3 h before increasing it by 9 km/h for the rest of the journey to Town J.
- How long did he take to complete the whole journey?
- What was his average speed from Town H to Town J?
(a)
Distance of 1st part of the journey
= 3 x 73
= 219 km
New speed for rest of the journey
= 73 + 9
= 82 km / h
Remaining distance for rest of the journey
= 712 - 219
= 493 km
Time taken for rest of the journey
= 493 ÷ 82
= 5 h
Total time taken
= 3 + 5
= 8 h
(b)
Average speed of the whole journey
= 712 ÷ 8
= 89 km
Answer(s): (a) 8 h; (b) 89km/h