4. In the following bank balance sheet, amounts are in millions of dollars. The required reserve ratio is 3% on the first $30 million ofcheckable deposits and 12% on any checkable deposit over $30 million. (3 points) Assets Equity and Liabilities Reserves $18.9 Loans Securities $31.1 Net worth Checkable deposits $20 $180 $150 Total $200 Total $200 a. Calculate the bank's excess reserves b. Suppose that the bank sells $5 million in securities to an investor. Show the bank's balance sheet after this transaction. Now what are the bank's excess reserves