Howard drove from Town K to Town L which was 648 km away. He started from Town K at an average speed of 73 km/h. He maintained this speed for 2 h before increasing it by 4 km/h for the rest of the journey to Town L.
- How long did he take to complete the whole journey?
- What was his average speed from Town K to Town L?
(a)
Distance of 1st part of the journey
= 2 x 73
= 146 km
New speed for rest of the journey
= 73 + 4
= 77 km / h
Remaining distance for rest of the journey
= 648 - 146
= 502 km
Time taken for rest of the journey
= 502 ÷ 77
= 6 h
Total time taken
= 2 + 6
= 8 h
(b)
Average speed of the whole journey
= 648 ÷ 8
= 81 km
Answer(s): (a) 8 h; (b) 81km/h