Modifying a solution that someone posted in another newsgroup, I set
up the following formulas:

B3: =rounddown(E2*8%,0)
Copy B3 to B4:B11
C2: =roundup(C1,0)
C3: =roundup(C2*(1+6%),0)
Copy C3 to C4:C10
D8: =roundup(fv(5%,6,0,-25000),0)
D9: =roundup(D8*(1+5%),0)
Copy D9 to D10:D11
E2: =C2
E3: =E2+B3+C3-D3
Copy E3 to E4:E11

I tried to use Excel Solver to find C1 that minimizes E11 subject to
the constraint E11 = 0.

First, if I do nothing more (i.e. leave C1 blank), Solver results in
C1 = 0.75 and E11 = -161,856, violating the constraint.

Arguably, that could be due to the Options that I selected, namely the
default. I tried setting the Iterations to the max (32767) and I have
played with some other Options, to no avail.

Even if I enter 9690 into C1, Solver results in C1 = 9689.527 and E11
= 73.

The best solution is 9685.5 <= C1 <= 9686, which results in E11 = 11.

How should I set up Solver so that it finds the best solution?

Can I expect to do that without entering something close to the right
solution in C1 in the first place?