Luis left City A for City Z at 09 35. Mary left City A for City C at the same time. At 14 35, they were 960 km apart. Both maintained a constant speed and reached their destination at the same time at 16 15.
- Find the distance between Cities A and C.
- If Mary was 79 the speed of Luis, find Luis's speed.
(a)
Time taken for Luis and Mary to travel 09 35 to 14 35 = 5 h
Time taken for Luis and Mary to travel 09 35 to 16 15 = 6 h 40 min = 6
4060 h = 6
23 h
Distance travelled by Luis and Mary in 1 hour
= 960 ÷ 5
= 192 km
Total distance
= 6
23 x 192
= 1280 km
(b)
Mary's distance : Luis's distance
7 : 9
Mary's speed : Luis's speed
7 : 9
16 u = 192 km
1 u = 192 ÷ 16 = 12 km
Luis's speed
= 9 u
= 9 x 12
= 108 km/h
Answer(s): (a) 1280 km; (b) 108km/h