John drove from Town L to Town M which was 380 km away. He started from Town L at an average speed of 61 km/h. He maintained this speed for 4 h before increasing it by 5 km/h for the rest of the journey to Town M.
- How long did he take to complete the whole journey?
- What was his average speed from Town L to Town M?
(a)
Distance of 1st part of the journey
= 4 x 61
= 244 km
New speed for rest of the journey
= 61 + 5
= 66 km / h
Remaining distance for rest of the journey
= 380 - 244
= 136 km
Time taken for rest of the journey
= 136 ÷ 66
= 1 h
Total time taken
= 4 + 1
= 5 h
(b)
Average speed of the whole journey
= 380 ÷ 5
= 76 km
Answer(s): (a) 5 h; (b) 76km/h