If the federal reserve rate was 7%, the money supply would be
30,000÷0.07=428,571
If the federal reserve rate was 5%, the money supply would be
30,000÷0.05=600,000
If the federal reserve decreases the reserve rate from 7% to 5%
600,000−428,571=171,429
The money supply increases by 171429
Hope it helps!