03p-0.25r-03q=0

0.8p-0.6r-0.05q=0
0.9p-0.15r-0.65q=0

I don't know if this help but i think p+q=1.

should there be decimal places in the first and third terms of

03p-0.25r-03q=0 ?

anyway, since all 3 constants are equal to zero, the solution would be (0,0,0)