Math problem: "It is known that there is an empirical formula for the relationship between the profits (expressed by P.Q million yuan respectively) obtained from operating two commodities A and B and the invested capital X (ten thousand yuan). ... Suppose a invests x profits y and b is 3-X.

Y= x/5+3/5 (3-x)

Let t= radical (3-x) x = 3-t 2.

∴y= 1/5(3-t^2)+3/5t=- 1/5(t- 1.5)^2+ 1.05

When t= 1.5, y= 1.05.

X=0.75 when t= 1.5.

That is, the investment of Party A and Party B is 0.75 and 22,500 yuan respectively, and the maximum profit is 654.38+0.500 yuan.