Suppose the required reserve ratio is 20 percent, and the Fed buys $1 million worth of bonds from the public. If the public deposits this amount into transactions accounts, the money supply will

Increase directly by $1 million and an additional lending capacity of $4 million will be created for the banking system.

Explanation:

The formula for increase in money supply is

Increase in money supply = (1 / Required reserve ratio) * Excess reserve.

Now, we have, required reserve ratio of 20%.

That means, out of $1 million deposit, required reserve = ($1,000,000 * 0.20) = $200,000.

Now, we knew that, Total reserve = required reserve + excess reserve

Total Reserve = $1,000,000 and required reserve = $200,000.

So, Excess reserve = $1,000,000 - $200,000 = $800,000.

Now, Increase in money supply = (1 / 0.20) * $800,000 = $4 million.

That means,

If the public deposits this amount into transactions accounts, the money supply will:

Increase directly by $1 million and an additional lending capacity of $4 million will be created for the banking system.