Justin drove from Town B to Town C which was 504 km away. He started from Town B at an average speed of 64 km/h. He maintained this speed for 4 h before increasing it by 10 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
= 4 x 64
= 256 km
New speed for rest of the journey
= 64 + 10
= 74 km / h
Remaining distance for rest of the journey
= 504 - 256
= 248 km
Time taken for rest of the journey
= 248 ÷ 74
= 2 h
Total time taken
= 4 + 2
= 6 h
(b)
Average speed of the whole journey
= 504 ÷ 6
= 84 km
Answer(s): (a) 6 h; (b) 84km/h