BobbyGo

As par for the course, this could probably have be made a lot more elegantly, but it seems to get the job done.

Fair warning: this took about 20 seconds to spit out an answer.  Feel free to uncomment the cout after the first for loop if you are really into countdowns.

int a, b, c, d, e, f, g, h, i, j, k, l, a1, b1, c1, d1, e1, f1, g1, h1, i1, j5, k1, l1, money=10000;

int main()
{
    for(a=35; a>=0; a--)
    {
        //cout<<a<<endl;
        for(b=((35-a)>20 ? 20 : (35-a)); b>=0; b--)
        {
            for(c=((35-(a+b))>30 ? 30 : (35-(a+b))); c>=0; c--)
            {
                d=35-(a+b+c);

                for(e=45-a; e>=0; e--)
                {
                    for(f=((50-e)>20 ? 20 : (50-e)); f>=0; f--)
                    {
                        for(g=((50-(e+f))>30 ? 30 : (50-(e+f))); g>=0; g--)
                        {
                            h=50-(e+f+g);

                            for(i=((a+e)<5 ? 0 : 45-(a+e)); i>=0; i--)
                            {
                                if(a+e+i==45)
                                {
                                    for(j=((40-i)>20 ? 20 : (40-i)); j>=0; j--)
                                    {
                                        if(b+f+j==20)
                                        {
                                            for(k=((40-(i+j))>30 ? 30 : (40-(i+j))); k>=0; k--)
                                            {
                                                if(c+g+k==30)
                                                {
                                                    l=40-(i+j+k);

                                                    if(d+h+l==30 and (8*a+6*b+10*c+9*d+9*e+12*f+13*g+7*h+14*i+9*j+16*k+5*l)<=money)
                                                    {
                                                        money=(8*a+6*b+10*c+9*d+9*e+12*f+13*g+7*h+14*i+9*j+16*k+5*l);
                                                        a1=a;b1=b;c1=c;d1=d;
                                                        e1=e;f1=f;g1=g;h1=h;
                                                        i1=i;j5=j;k1=k;l1=l;
                                                    }
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
    }

    cout<<a1<<"  "<<b1<<"  "<<c1<<"  "<<d1<<endl<<e1<<"  "<<f1<<"  "<<g1<<"  "<<h1<<endl<<i1<<"  "<<j5<<"  "<<k1<<"  "<<l1<<endl<<"= $"<<money<<endl;
	return 0;
}

Okay, fine.  The maximum revenue is produced by making 2 desks, 0 tables, and 8 chairs for a total of $280.

double d, t, c, d1, t1, c1, money=0;

int main()
{
    for(d=0; d<5; d++)
    {
        for(t=0; t<7; t++)
        {
            for(c=0; c<15; c++)
            {
                if(d*2 + t*1.5 + c*.5 <= 8 and d*4 + t*2 + c*1.5 <= 20 and d*8 + t*6 + c*1 <=48 and d*60 + t*30 + c*20 > money)
                {
                    money = d*60 + t*30 + c*20;
                    d1 = d;
                    t1 = t;
                    c1 = c;
                }
            }
        }
    }

    cout<<d1<<" desks, "<<t1<<"  tables, and "<<c1<<" chairs makes: $"<<money<<endl;
	return 0;
}