Please help me calculate on excel please, I need to know how to solve on excel. Show me spreadsheet.

The minimum cash balance of $20,000 is required at in the Village of Sarah towns general fund cash account. Transferring out of the account requires payment of $550 per transaction. Inspection of the variation of the account balance over the last year showed variation of $9,000,000. The monthly interest rate is 0.0055. Calculate the following items:

1. The spread between the upper and lower limits

2. The upper limit

3. The return point

Explain your investment strategy to the village manager in 2-3 sentences.