Rael drove from Town Z to Town A which was 450 km away. He started from Town Z at an average speed of 80 km/h. He maintained this speed for 4 h before increasing it by 9 km/h for the rest of the journey to Town A.
- How long did he take to complete the whole journey?
- What was his average speed from Town Z to Town A?
(a)
Distance of 1st part of the journey
= 4 x 80
= 320 km
New speed for rest of the journey
= 80 + 9
= 89 km / h
Remaining distance for rest of the journey
= 450 - 320
= 130 km
Time taken for rest of the journey
= 130 ÷ 89
= 1 h
Total time taken
= 4 + 1
= 5 h
(b)
Average speed of the whole journey
= 450 ÷ 5
= 90 km
Answer(s): (a) 5 h; (b) 90km/h