Maximum loan amount calculation

Hi guys

I'm hoping someone out there can help me.

I need a script/function that works in "classic asp" that will allow me to display the maximum loan amount a user can borrow based on:

1. The monthly payment they can afford
2. The interest rate charged by the lender
3. The number of months the loan will be paid over

In practical terms, I need to know the total loan amount available. For example, if someone can afford to pay back the lender £200 per month at a rate of 5.5% over the period of 36 months then how much can they borrow?

Ideally, I would just add in the values (200, 5.5, 36) into my function and my page would simply display the maximum loan amount.

I have tried to find a solution for the best part of two weeks and it's driving me mad.

Any help would be fully appreciated

Best regards

Rod from the UK