Management of Accounts Receivalbe and Payable

Dear Sir,

I would like to request to explain following question and what the answer is?
1) Foster co is considering implementing a new cash collection system at a cost of $80,000 per year. annual sales are $90 million and the new system will reduce collection time by three days.
if Foster can invest surplus funds at 8% per annum, what is the net gain/(loss) from implementing the new system? assume a 360 a day year.
2) Average daily cash outflows are $3M for Evans Co. A new cash management system can add two days to the cash payments schedule. Evans can earn 10% per annum on surplus funds.
What is the maximum amount that Evans should be willing to pay each year for this cash management system?
3) The following items were extracted from a company’s budget for next month:
Purchase on credit 360,000
Expected decrease in inventory over the month 12,000
Expected increase in trade payable over the month 15,000
What is the budgeted payment to trade payables for the month?

Thank you Sir.

Best Regards,

May