Vaidev drove from Town K to Town L which was 390 km away. He started from Town K at an average speed of 60 km/h. He maintained this speed for 3 h before increasing it by 8 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
= 3 x 60
= 180 km
New speed for rest of the journey
= 60 + 8
= 68 km / h
Remaining distance for rest of the journey
= 390 - 180
= 210 km
Time taken for rest of the journey
= 210 ÷ 68
= 2 h
Total time taken
= 3 + 2
= 5 h
(b)
Average speed of the whole journey
= 390 ÷ 5
= 78 km
Answer(s): (a) 5 h; (b) 78km/h