Zane drove from Town C to Town D which was 456 km away. He started from Town C at an average speed of 63 km/h. He maintained this speed for 4 h before increasing it by 4 km/h for the rest of the journey to Town D.
- How long did he take to complete the whole journey?
- What was his average speed from Town C to Town D?
(a)
Distance of 1st part of the journey
= 4 x 63
= 252 km
New speed for rest of the journey
= 63 + 4
= 67 km / h
Remaining distance for rest of the journey
= 456 - 252
= 204 km
Time taken for rest of the journey
= 204 ÷ 67
= 2 h
Total time taken
= 4 + 2
= 6 h
(b)
Average speed of the whole journey
= 456 ÷ 6
= 76 km
Answer(s): (a) 6 h; (b) 76km/h