Answer:
the Fed should sell $10 billion in securities
Step-by-step explanation:
intended goal is to decrease money supply by $100 billion
banks' required reserve ratio = 10%
money multiplier = 1 / reserve ratio = 1 / 10% = 10
the Fed should sell $10 billion in securities
total effect = -$10 billion x 10 (money multiplier) = -$100 billion
When the Fed sells securities, it is absorbing money, so it reduces the monetary base and money supply of the economy.