P6 math problem sum

This is the question:

At 12pm, Car A left Town X for Town Y while Car B left Town Y for Town X.

At 8pm, the two cars passed each other.

5 hours later, Car A reached Town Y but Car B was still 150km from Town X.

Find the distance between Town X and Town Y.

many thanks!!

It takes A 5 hours to travel the distance travelled by B in 8 hours. thus, we can conclude that

speed of A : speed of B = 8 : 5

Let the speed of A be 8u and that of B be 5u

Distance between X and Y = 8u x 13 = 104u (speed of A x 13hours)

In 13 hours, B has travelled 5u x 13 = 65u, which is still 150km less than 104u.

Thus, 104u - 65u =150

39u =150

1u = 50/13

Distance between X and Y = 104u = 50/13 x 104 = 400km