David left City T for City S at 06 37. Xuan left City T for City C at the same time. At 10 37, they were 576 km apart. Both maintained a constant speed and reached their destination at the same time at 13 12.
- Find the distance between Cities A and C.
- If Xuan was 35 the speed of David, find David's speed.
(a)
Time taken for David and Xuan to travel 06 37 to 10 37 = 4 h
Time taken for David and Xuan to travel 06 37 to 13 12 = 6 h 35 min = 6
3560 h = 6
712 h
Distance travelled by David and Xuan in 1 hour
= 576 ÷ 4
= 144 km
Total distance
= 6
712 x 144
= 948 km
(b)
Xuan's distance : David's distance
3 : 5
Xuan's speed : David's speed
3 : 5
8 u = 144 km
1 u = 144 ÷ 8 = 18 km
David's speed
= 5 u
= 5 x 18
= 90 km/h
Answer(s): (a) 948 km; (b) 90km/h