Carl drove from Town R to Town S which was 712 km away. He started from Town R at an average speed of 70 km/h. He maintained this speed for 2 h before increasing it by 10 km/h for the rest of the journey to Town S.
- How long did he take to complete the whole journey?
- What was his average speed from Town R to Town S?
(a)
Distance of 1st part of the journey
= 2 x 70
= 140 km
New speed for rest of the journey
= 70 + 10
= 80 km / h
Remaining distance for rest of the journey
= 712 - 140
= 572 km
Time taken for rest of the journey
= 572 ÷ 80
= 6 h
Total time taken
= 2 + 6
= 8 h
(b)
Average speed of the whole journey
= 712 ÷ 8
= 89 km
Answer(s): (a) 8 h; (b) 89km/h