[dba-Tech] Excel goal seek

I'm trying to use Goal Seek to calculate the different components of a 
savings account. I've set it up and Goal Seek works correctly to determine 
the amount of each regular deposit.

However, using the same spreadsheet, I can't get Goal Seek to calculate the 
number of deposits or the interest rate for a specific future value.

I've entered the following formula in cell D2: =FV(C2,A2,B2)

If cells A2 and C2 equal 24 and .02, respectively,  I can return the amount 
of each deposit (164) to B2 using Goal Seek to find a future value of 5000.

Similarly, if cells A2 and B2 equal 24 and 164, respectively, Goal Seek 
returns an interest rate of 219... um... no.

If cells B2 and C2 equal 200 and .02, respectively, Goal Seek returns 48 for 
the number of deposits.

The percentage rate format seems to be the culprit -- no matter what I 
format the cell as, Goal Seek seems to ignore me -- at least that's how it 
seems. I'm sure this is a simple question of me not knowing the right 
formula for D2 or I'm totally misunderstanding how Goal Seek works.

In addition, why does Goal Seek always return a negative value?

Susan H.