John drove from Town Q to Town R which was 624 km away. He started from Town Q at an average speed of 63 km/h. He maintained this speed for 2 h before increasing it by 8 km/h for the rest of the journey to Town R.
- How long did he take to complete the whole journey?
- What was his average speed from Town Q to Town R?
(a)
Distance of 1st part of the journey
= 2 x 63
= 126 km
New speed for rest of the journey
= 63 + 8
= 71 km / h
Remaining distance for rest of the journey
= 624 - 126
= 498 km
Time taken for rest of the journey
= 498 ÷ 71
= 6 h
Total time taken
= 2 + 6
= 8 h
(b)
Average speed of the whole journey
= 624 ÷ 8
= 78 km
Answer(s): (a) 8 h; (b) 78km/h