Answer:
Their income after 20 years would be 72,550 dollars.
Explanation:
The income after 20 years can easily de determin by using compounding
formula
Future Value = Present Value (1 + I)^ 20
           = 90,000 (1 + 0.03)^ 20
           = 162,550 dollars
Income can be determing by subtracting Pv from Fv i.e
Income = 162,550 - 90,000 = 72,550
Calculation on excel sheet
    A             B          C             D        Â
1 Â Â 90,000 Â Â Â Â Â Â 1.03 Â Â Â Â Â Â = A1 * 1.03 Â Â Â Â = C1-A1 Â Â Â Â
2 Â Â Â = D1 Â Â Â Â Â Â Â Â Â 1.03 Â Â Â Â Â = A2 * 1.03 Â Â Â = C2-A2
20 Â Â = D19 Â Â Â Â Â Â Â 1.03 Â Â Â Â Â = A20 * 1.03 Â Â Â = A20 - C20
* In work sheet colunm D will show income on investment.