Hi. I wanted ideas on how to make a spreadsheet for the following example of a business:
Basically it is a business dealing with selling airtime. If say we have 3 network service providers A B and C. Sales of airtime for network A gives a 5% profit of your sales while network B and C give 6%. A scenario to picture this is say you have loaded $200 worth of stock and then someone purchases $20 of A, $10 of B and $5 of C so your remaining balance is calculated as follows;
$200-($20+$10+$5)+[($20x5%)+($10x6%)+($5x6%)] which would give you $66.9

The spreadsheet should take into account the profit made after the the stock has run out. It should update the balance after new stock is added and finally it should have record of the customers purchases and it should be able to update the balance owing after part of a payment is made by the customer.