Jack left City M for City L at 05 48. Sarah left City M for City C at the same time. At 10 48, they were 800 km apart. Both maintained a constant speed and reached their destination at the same time at 12 12.
- Find the distance between Cities A and C.
- If Sarah was 79 the speed of Jack, find Jack's speed.
(a)
Time taken for Jack and Sarah to travel 05 48 to 10 48 = 5 h
Time taken for Jack and Sarah to travel 05 48 to 12 12 = 6 h 24 min = 6
2460 h = 6
25 h
Distance travelled by Jack and Sarah in 1 hour
= 800 ÷ 5
= 160 km
Total distance
= 6
25 x 160
= 1024 km
(b)
Sarah's distance : Jack's distance
7 : 9
Sarah's speed : Jack's speed
7 : 9
16 u = 160 km
1 u = 160 ÷ 16 = 10 km
Jack's speed
= 9 u
= 9 x 10
= 90 km/h
Answer(s): (a) 1024 km; (b) 90km/h