Answer: Money Supply Decrease of $50 million.
Explanation:
$40 million was deposited while $50 million was withdrawn.
The net change in the banking system would therefore be,
= 40 - 50
= -$10 million
($10 million ) means that more money left than came in.
The money supply can be calculated as the net change multiplied by the money multiplier.
The Money Multiplier is denoted as 1/reserve requirement.
Change in Money Supply is,
= -10 million * 1/20%
= -$50 million
Going by the negative number it means that Money Supply reduces by $50 million.