David drove from Town Z to Town A which was 704 km away. He started from Town Z at an average speed of 69 km/h. He maintained this speed for 2 h before increasing it by 4 km/h for the rest of the journey to Town A.
- How long did he take to complete the whole journey?
- What was his average speed from Town Z to Town A?
(a)
Distance of 1st part of the journey
= 2 x 69
= 138 km
New speed for rest of the journey
= 69 + 4
= 73 km / h
Remaining distance for rest of the journey
= 704 - 138
= 566 km
Time taken for rest of the journey
= 566 ÷ 73
= 6 h
Total time taken
= 2 + 6
= 8 h
(b)
Average speed of the whole journey
= 704 ÷ 8
= 88 km
Answer(s): (a) 8 h; (b) 88km/h