Japheth drove from Town S to Town T which was 340 km away. He started from Town S at an average speed of 72 km/h. He maintained this speed for 2 h before increasing it by 4 km/h for the rest of the journey to Town T.
- How long did he take to complete the whole journey?
- What was his average speed from Town S to Town T?
(a)
Distance of 1st part of the journey
= 2 x 72
= 144 km
New speed for rest of the journey
= 72 + 4
= 76 km / h
Remaining distance for rest of the journey
= 340 - 144
= 196 km
Time taken for rest of the journey
= 196 ÷ 76
= 2 h
Total time taken
= 2 + 2
= 4 h
(b)
Average speed of the whole journey
= 340 ÷ 4
= 85 km
Answer(s): (a) 4 h; (b) 85km/h