Will drove from Town R to Town S which was 430 km away. He started from Town R at an average speed of 71 km/h. He maintained this speed for 4 h before increasing it by 4 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
= 4 x 71
= 284 km
New speed for rest of the journey
= 71 + 4
= 75 km / h
Remaining distance for rest of the journey
= 430 - 284
= 146 km
Time taken for rest of the journey
= 146 ÷ 75
= 1 h
Total time taken
= 4 + 1
= 5 h
(b)
Average speed of the whole journey
= 430 ÷ 5
= 86 km
Answer(s): (a) 5 h; (b) 86km/h