Oliver drove from Town D to Town E which was 395 km away. He started from Town D at an average speed of 76 km/h. He maintained this speed for 2 h before increasing it by 9 km/h for the rest of the journey to Town E.
- How long did he take to complete the whole journey?
- What was his average speed from Town D to Town E?
(a)
Distance of 1st part of the journey
= 2 x 76
= 152 km
New speed for rest of the journey
= 76 + 9
= 85 km / h
Remaining distance for rest of the journey
= 395 - 152
= 243 km
Time taken for rest of the journey
= 243 ÷ 85
= 3 h
Total time taken
= 2 + 3
= 5 h
(b)
Average speed of the whole journey
= 395 ÷ 5
= 79 km
Answer(s): (a) 5 h; (b) 79km/h