(1) Let the speed of upstream sailing be xkm, and it is known that downstream sailing is 12/8x, that is, 3/2xkm.

120/x= 120/(3/2)x+2

120/x=80/x+2

120=80+2x

2x= 120-80

2x=40

x=20

The speed of sailing against the current is 20 kilometers.

(2) Let the bus speed be xkm and the car speed be 5/2km.

135/x-5 = 135/(5/2)x-0.5

135/x-5=54/x-0.5

135-5x=54-0.5x

5x-0.5x= 135-54

4.5x=8 1

x= 18

5/2x=5/2× 18=45

The bus speed is 45km/h, and the car speed is 18km/h.