If a $500 billion increase in investment spending increases income by $500 billion in the first round of the multiplier process and by $450 in the second round, income will eventually increase by .

450 billion

Explanation:

Marginal Propensity to consume (MPC) is a ratio that measure much the investment in the economy is consumed.

Marginal Propensity to save (MPS) is a ratio that measure much the investment in the economy is saved

Marginal Consumption = $500 billion - 450 billion = 50 billion

Spending ratio = 50 / 500 = 0.1

Marginal Propensity to consume (MPC) = 0.1

Marginal Propensity to save (MPS) = 1 - 0.1 = 0.9

Spending Multiplier = 1 / MPS  = 1 / 0.9 = 1.11

First Round of Multiplier

Spending 500 billion increase income 500 billion

after consuming 50 billion

In second round Spending 450 billion will increase the income by 450 billion

if you use only 25 for your entertainment and only 200 for the groceries that you really need and take out the 50 per month for the computer then that should be enough