Riordan left City S for City R at 06 35. Xuan left City S for City C at the same time. At 10 35, they were 672 km apart. Both maintained a constant speed and reached their destination at the same time at 12 10.
- Find the distance between Cities A and C.
- If Xuan was 57 the speed of Riordan, find Riordan's speed.
(a)
Time taken for Riordan and Xuan to travel 06 35 to 10 35 = 4 h
Time taken for Riordan and Xuan to travel 06 35 to 12 10 = 5 h 35 min = 5
3560 h = 5
712 h
Distance travelled by Riordan and Xuan in 1 hour
= 672 ÷ 4
= 168 km
Total distance
= 5
712 x 168
= 938 km
(b)
Xuan's distance : Riordan's distance
5 : 7
Xuan's speed : Riordan's speed
5 : 7
12 u = 168 km
1 u = 168 ÷ 12 = 14 km
Riordan's speed
= 7 u
= 7 x 14
= 98 km/h
Answer(s): (a) 938 km; (b) 98km/h