Answer and Explanation:
The computation is shown below:
1. a) fewer; less checkable deposits
As if the government securities are sold so it reduce the reserves and the bank checkable deposits
b) decreases; $500 million
As if the government securities are sold by the Fed that reduced the money supply
Here it is a reduction of
= 1 ÷ Required reserve ratio × Selling price of securities
= 1 ÷ 0.20 × 100
= $500 million