Sam drove from Town J to Town K which was 380 km away. He started from Town J at an average speed of 64 km/h. He maintained this speed for 2 h before increasing it by 4 km/h for the rest of the journey to Town K.
- How long did he take to complete the whole journey?
- What was his average speed from Town J to Town K?
(a)
Distance of 1st part of the journey
= 2 x 64
= 128 km
New speed for rest of the journey
= 64 + 4
= 68 km / h
Remaining distance for rest of the journey
= 380 - 128
= 252 km
Time taken for rest of the journey
= 252 ÷ 68
= 3 h
Total time taken
= 2 + 3
= 5 h
(b)
Average speed of the whole journey
= 380 ÷ 5
= 76 km
Answer(s): (a) 5 h; (b) 76km/h