Sam drove from Town K to Town L which was 609 km away. He started from Town K at an average speed of 63 km/h. He maintained this speed for 4 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
= 4 x 63
= 252 km
New speed for rest of the journey
= 63 + 4
= 67 km / h
Remaining distance for rest of the journey
= 609 - 252
= 357 km
Time taken for rest of the journey
= 357 ÷ 67
= 3 h
Total time taken
= 4 + 3
= 7 h
(b)
Average speed of the whole journey
= 609 ÷ 7
= 87 km
Answer(s): (a) 7 h; (b) 87km/h