Speed P6

Car A and Car B left Town Y at the same time, heading in the opposite direction. Car A headed for Town Z while Car B left for Town X. The speed of Car B was 20 km/h faster than Car A. After 1/2 h, Car A had completed 2/3 of its journey while Car B had completed 1/2 of its journey. The two cars were also 110 km apart.
a) Calculate the speed of Car A.
b) How far was Car B from Town X when Car A reached its destination ?


       Car A                Car B
Z               Y                                 X
 [   ][   ][   ][    ] [][   ][][    ][][    ][]
      <---- 110 km ------>

20 x 1/2 = 10 km              [][]

4u --> 110 - 10 = 100
1 u --> 100 / 4 = 25

2 u --> 2 x 25 = 50 km
50/ (1/2) = 50 x 2
                = 100 km/h         Speed of car

a) The speed of Car A was 100 km/h.

2/3 --> 1/2 h
3/3 --> 3/2 x 1/2 = 3/4 h

1/2 h --> 50 + 10 = 60 km
3/4 h --> 3/4 x 2 x 60 = 90 km

60 x 2 - 90 = 30 km

b) Car B was 30 km from Town X.