Luis drove from Town K to Town L which was 420 km away. He started from Town K at an average speed of 62 km/h. He maintained this speed for 4 h before increasing it by 10 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
= 4 x 62
= 248 km
New speed for rest of the journey
= 62 + 10
= 72 km / h
Remaining distance for rest of the journey
= 420 - 248
= 172 km
Time taken for rest of the journey
= 172 ÷ 72
= 2 h
Total time taken
= 4 + 2
= 6 h
(b)
Average speed of the whole journey
= 420 ÷ 6
= 70 km
Answer(s): (a) 6 h; (b) 70km/h