Japheth drove from Town G to Town H which was 712 km away. He started from Town G at an average speed of 69 km/h. He maintained this speed for 4 h before increasing it by 9 km/h for the rest of the journey to Town H.
- How long did he take to complete the whole journey?
- What was his average speed from Town G to Town H?
(a)
Distance of 1st part of the journey
= 4 x 69
= 276 km
New speed for rest of the journey
= 69 + 9
= 78 km / h
Remaining distance for rest of the journey
= 712 - 276
= 436 km
Time taken for rest of the journey
= 436 ÷ 78
= 4 h
Total time taken
= 4 + 4
= 8 h
(b)
Average speed of the whole journey
= 712 ÷ 8
= 89 km
Answer(s): (a) 8 h; (b) 89km/h