You need to withdraw money from an interest-bearing savings account A into a short-term, daily use cash account B, where B is much like a petty cash account. You move money from A to B so that you can pay for various needs. Every time you withdrawal money from A and put it into B, you must pay a $10 service few no matter how much you withdraw. You must have enough in account B to meet any requirements for that day - you must pay on time. So for instance, if you move 6,000 into account B on Day 1 so that you can meet payments of 4,000 today (Day 1) and 2,000 tomorrow (Day 2), then you will need to withdraw more on Day 3 to meet whatever requirements you might have.

On Monday morning, you have $3000 in cash on hand in the daily use account. For the next seven days, the cash requirements are given and these must be met. At the beginning of each day, you must decide how much money (if any) to withdraw from the interest-bearing account into the daily cash account. It costs $10 to make a withdrawal of any size. You believe that the opportunity cost of having $1 of cash on hand for a year is $0.20.  Assume that opportunity costs are incurred on each day’s ending balance ($0.20/365).  If you pull money from an account that pays interest when you don't need it that day, then you are forgoing the interest for that day - an opportunity cost. 

Determine how much money you should withdraw from the bank during each of the next seven days.

Formulate the written model and develop the solver model in this spreadsheet, then solve using solver.

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