Market researchers often report disposable income. This is your income after tax deductions. Your gross income is $3,000 per month. Your federal tax is 10%, state tax is 5%, city tax is 2%, and you pay 7% to social security. What is your monthly disposable income?

To solve this problem, take your gross income of $3,000 and multiply it by each percentage rate that you pay from it. Once that's done, you can subtract all of the amounts and receive the disposable income.

($3,000) (.10) = $300

($3,000) (.05) = $150

($3,000) (.02) = $60

($3,000) (.07) = $210

Add these numbers:

($300 + $150 + $60 + $210) = $710

Then take $710 and subtract from $3,000:

$3,000 - $710 = $2,280

Income=gross income-deductions.

Let's make your income Y.

Y=3000 - (3000x (.1+.5+.2+.7)

Y=3000 - (3000 (.15))

Y=3000 - (450)

Y=2550.

Your total disposable income is $2,550.