Final answer:
The currency drain ratio is 0.65% and the banks' reserve ratio is 1.29%.
Step-by-step explanation:
The currency drain ratio is calculated by dividing the amount of currency held by individuals and businesses by the total amount of deposits. In this case, the currency drain ratio is ($50 billion / $7,750 billion) * 100 = 0.65%.
The banks' reserve ratio is calculated by dividing the amount of reserves held by banks by the total amount of deposits. In this case, the banks' reserve ratio is ($100 billion / $7,750 billion) * 100 = 1.29%.