Ken drove from Town B to Town C which was 450 km away. He started from Town B at an average speed of 79 km/h. He maintained this speed for 3 h before increasing it by 8 km/h for the rest of the journey to Town C.
- How long did he take to complete the whole journey?
- What was his average speed from Town B to Town C?
(a)
Distance of 1st part of the journey
= 3 x 79
= 237 km
New speed for rest of the journey
= 79 + 8
= 87 km / h
Remaining distance for rest of the journey
= 450 - 237
= 213 km
Time taken for rest of the journey
= 213 ÷ 87
= 2 h
Total time taken
= 3 + 2
= 5 h
(b)
Average speed of the whole journey
= 450 ÷ 5
= 90 km
Answer(s): (a) 5 h; (b) 90km/h