This statement is true.
This statement has two aspects to it. In order for the statement as a whole to be true, both aspects must be true. Since they are both true, the statement as a whole is true as well.
One aspect of the statement is that the Federal Open Market Committee (FOMC) meets in Washington, D.C. This is true. The FOMC meets in the offices of the Board of Governors of the Federal Reserve System, which is in Washington, D.C.
The second aspect of the statement is that the decisions that the FOMC makes are not actually carried out in Washington. This aspect of the statement is also true. As can be seen in this link, the decisions are carried out in New York. The document in the link tells us that open market operations “are conducted by the Trading Desk at the Federal Reserve Bank of New York.”
Thus, both aspects of the statement are true and the statement as a whole is true as well.