Answer:
Reserve requirement = 20% or 0.250
Simple money multiplier = 1/Reserve Ratio = 1/0.2 = 5
Note that,
Increase in money supply = Increase in total reserves * Simple money multiplier
$100 Billion = Increase in total reserves * 5
Increase in total reserves = $20 billion
This means that the federal reserve should decrease the reserve requirement by purchasing $20 billion worth of US government bonds from banks, which will lead to increase of $100 billion in money supply.
