Tim drove from Town Y to Town Z which was 540 km away. He started from Town Y at an average speed of 78 km/h. He maintained this speed for 3 h before increasing it by 9 km/h for the rest of the journey to Town Z.
- How long did he take to complete the whole journey?
- What was his average speed from Town Y to Town Z?
(a)
Distance of 1st part of the journey
= 3 x 78
= 234 km
New speed for rest of the journey
= 78 + 9
= 87 km / h
Remaining distance for rest of the journey
= 540 - 234
= 306 km
Time taken for rest of the journey
= 306 ÷ 87
= 3 h
Total time taken
= 3 + 3
= 6 h
(b)
Average speed of the whole journey
= 540 ÷ 6
= 90 km
Answer(s): (a) 6 h; (b) 90km/h