Jack started driving from City R towards City S at 14 40 at an average speed of 60 km/h. Jeremy began driving from City R towards City S at 17 30 at an average speed of 110 km/h.
- At what time did Jeremy pass Jack on the road?
- 1110 hours after passing Jack, Jeremy reached City S. At what time did Jack reach City S?
(a)
From 14 40 to 17 30 = 2 h 50 min
Time that Jack travelled before Jeremy started driving = 2 h 50 min
1 h = 60 min
2 h 50 min = 2
5060 h = 2
56 h
Distance that Jack travelled before Jeremy started driving
= 2
56 x 60
=
176 x 60
= 170 km
Difference between Jeremy's and Jack's speed
= 110 - 60
= 50 km/h
Time that Jeremy took to catch up with Jack
= 170 ÷ 50
= 3.4 h
= 3 h 24 min
3 h 24 min after 17 30 = 20 54
Time that Jeremy passed Jack on the road = 20 54
(b)
1
110 h = 1 h 6 min
Total time that Jeremy travelled
= 1 h 6 min + 3 h 24 min
= 4 h 30 min
4 h 30 min = 4
3060h = 4
12h
Distance between City R and City S
= 4
12 x 110
= 495 km
Time that Jack travelled from City R to City S
= 495 ÷ 60
= 8.25 h
= 8 h 15 min
8 h 15 min after 14 40 = 22 55
Time that Jack reached City S = 22 55
Answer: (a) 20 54; (b) 22 55