Help me please!

Consider a closed economy that has a one bank only with deposits of 750,000 $ and required reserves ratio of 10%. a. How much can the bank loan out. b. Find the money multiplier. c. Find the money supply generated by this bank. d. Assume that the required reserves ratio increased to 20%. Compute the change in the money supply resulting from this increase. e. Assuming again that the required reserves ratio is 20%, calculate the excess reserves if the bank loaned out 500,000 only