a$).$ Calculate excess reserves when required reserve ratio on demand deposit is $14\%$ and required reserve ratio on time deposit is $3\%.$

b$).$ suppose that required reserve ratios are changed to $16\%$ on demand deposits and $0\%$ on time deposits. Calculate excess reserves

c$.$ suppose bank sells $3$ million in securities on the open market. Calculate the change in the bank$$s excess reserves when the required reserve ratio on demand deposits is $14\%$