Japheth drove from Town C to Town D which was 581 km away. He started from Town C at an average speed of 69 km/h. He maintained this speed for 3 h before increasing it by 6 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
= 3 x 69
= 207 km
New speed for rest of the journey
= 69 + 6
= 75 km / h
Remaining distance for rest of the journey
= 581 - 207
= 374 km
Time taken for rest of the journey
= 374 ÷ 75
= 4 h
Total time taken
= 3 + 4
= 7 h
(b)
Average speed of the whole journey
= 581 ÷ 7
= 83 km
Answer(s): (a) 7 h; (b) 83km/h