Peter left City A for City Z at 08 47. Risa left City A for City C at the same time. At 10 47, they were 320 km apart. Both maintained a constant speed and reached their destination at the same time at 14 44.
- Find the distance between Cities A and C.
- If Risa was 79 the speed of Peter, find Peter's speed.
(a)
Time taken for Peter and Risa to travel 08 47 to 10 47 = 2 h
Time taken for Peter and Risa to travel 08 47 to 14 44 = 5 h 57 min = 5
5760 h = 5
1920 h
Distance travelled by Peter and Risa in 1 hour
= 320 ÷ 2
= 160 km
Total distance
= 5
1920 x 160
= 952 km
(b)
Risa's distance : Peter's distance
7 : 9
Risa's speed : Peter's speed
7 : 9
16 u = 160 km
1 u = 160 ÷ 16 = 10 km
Peter's speed
= 9 u
= 9 x 10
= 90 km/h
Answer(s): (a) 952 km; (b) 90km/h