Dylan drove from Town Y to Town Z which was 553 km away. He started from Town Y at an average speed of 60 km/h. He maintained this speed for 2 h before increasing it by 4 km/h for the rest of the journey to Town Z.
- How long did he take to complete the whole journey?
- What was his average speed from Town Y to Town Z?
(a)
Distance of 1st part of the journey
= 2 x 60
= 120 km
New speed for rest of the journey
= 60 + 4
= 64 km / h
Remaining distance for rest of the journey
= 553 - 120
= 433 km
Time taken for rest of the journey
= 433 ÷ 64
= 5 h
Total time taken
= 2 + 5
= 7 h
(b)
Average speed of the whole journey
= 553 ÷ 7
= 79 km
Answer(s): (a) 7 h; (b) 79km/h