Why would the Fed seldom do an open market purchase of government securities at the same time

Question:

Why would the Fed seldom do an open market purchase of government securities at the same time that it raises the or the required reserve ratio?

Discount Rate
Depending upon the context, the discount rate has two different definitions and usages. First, the discount rate refers to the interest rate charged to the commercial banks and other financial institutions for the loans they take from the Federal...