Tom drove from Town C to Town D which was 385 km away. He started from Town C at an average speed of 61 km/h. He maintained this speed for 2 h before increasing it by 4 km/h for the rest of the journey to Town D.
- How long did he take to complete the whole journey?
- What was his average speed from Town C to Town D?
(a)
Distance of 1st part of the journey
= 2 x 61
= 122 km
New speed for rest of the journey
= 61 + 4
= 65 km / h
Remaining distance for rest of the journey
= 385 - 122
= 263 km
Time taken for rest of the journey
= 263 ÷ 65
= 3 h
Total time taken
= 2 + 3
= 5 h
(b)
Average speed of the whole journey
= 385 ÷ 5
= 77 km
Answer(s): (a) 5 h; (b) 77km/h