This problem is about percentages.
The total earnings are $72,000.
We know that income tax is 16%, Social Security is 6.2% and Medicare tax is 1.45%. To find the total amount of money Petunia pays in taxes, we need to multiply her earnings with each percentage in decimals, remember that 16% is 0.16, 6.2% is 0.062 and 1.45% is 0.0145.
Income tax
[tex]I=72,000\cdot0.16=11,520[/tex]Social Security
[tex]S=72,000\cdot0.062=4,464[/tex]Medicare tax
[tex]M=72,000\cdot0.0145=1,044[/tex]So, the total amount of money paid would be the sum
[tex]T=11,520+4,464+1,044=17,028[/tex]