Carl started driving from City S towards City T at 15 30 at an average speed of 60 km/h. Fred began driving from City S towards City T at 17 10 at an average speed of 100 km/h.
- At what time did Fred pass Carl on the road?
- 114 hours after passing Carl, Fred reached City T. At what time did Carl reach City T?
(a)
From 15 30 to 17 10 = 1 h 40 min
Time that Carl travelled before Fred started driving = 1 h 40 min
1 h = 60 min
1 h 40 min = 1
4060 h = 1
23 h
Distance that Carl travelled before Fred started driving
= 1
23 x 60
=
53 x 60
= 100 km
Difference between Fred's and Carl's speed
= 100 - 60
= 40 km/h
Time that Fred took to catch up with Carl
= 100 ÷ 40
= 2.5 h
= 2 h 30 min
2 h 30 min after 17 10 = 19 40
Time that Fred passed Carl on the road = 19 40
(b)
1
14 h = 1 h 15 min
Total time that Fred travelled
= 1 h 15 min + 2 h 30 min
= 3 h 45 min
3 h 45 min = 3
4560h = 3
34h
Distance between City S and City T
= 3
34 x 100
= 375 km
Time that Carl travelled from City S to City T
= 375 ÷ 60
= 6.25 h
= 6 h 15 min
6 h 15 min after 15 30 = 21 45
Time that Carl reached City T = 21 45
Answer: (a) 19 40; (b) 21 45