According to the meaning, 3x+2y+z=3 15 x+2y+3z=285.

X=z+ 15 and 2z+y= 135 can be obtained. There are countless solutions.

In addition, it can be found that 600 yuan is needed to buy 4 pieces A, 4 pieces B and 4 pieces C, that is, 1 pieces A, B and C need 150 yuan;