Simon drove from Town D to Town E which was 623 km away. He started from Town D at an average speed of 80 km/h. He maintained this speed for 2 h before increasing it by 5 km/h for the rest of the journey to Town E.
- How long did he take to complete the whole journey?
- What was his average speed from Town D to Town E?
(a)
Distance of 1st part of the journey
= 2 x 80
= 160 km
New speed for rest of the journey
= 80 + 5
= 85 km / h
Remaining distance for rest of the journey
= 623 - 160
= 463 km
Time taken for rest of the journey
= 463 ÷ 85
= 5 h
Total time taken
= 2 + 5
= 7 h
(b)
Average speed of the whole journey
= 623 ÷ 7
= 89 km
Answer(s): (a) 7 h; (b) 89km/h