Answer:
$45 billion
Explanation:
As per the data given in the question,
Marginal propensity to consume(MPC) = 0.9
Multiplier = 1 ÷ (1-MPC)
= 1 ÷ (1-0.9)
= 1 ÷ 0.1
= 10
Required change in money supply = $450 billion
Investment needed = Expansion ÷ Multiplier
= $450 ÷ 10
= $45 billion
Therefore, Least amount which can be spent by government to overcome the $450 billion gap = $45 billion