Final answer:
The excess reserves of Bank A have increased by $4500.
Step-by-step explanation:
To find the increase in excess reserves of Bank A, we need to determine the increase in required reserves caused by the deposit. The target reserve ratio is 10%, so Bank A must hold 10% of the deposit as required reserves.
Required reserves = Deposit * Reserve ratio
Required reserves = $45000 * 0.10
Required reserves = $4500
The increase in excess reserves is equal to the increase in required reserves. Therefore, the excess reserves of Bank A have increased by $4500.