There are different slab rates for income tax given.
We are to calculate the tax for Mary Hernandez. Her income is 43000 dollars.
Hence she comes in the slab of 31850-77100
1) Earned income = 43000 dollars
2) Base amount = 4386 (refer slab amount)
3) The amount over base amount = 43000-31850 = 11150 dollars.
4) Multiplied by 25% = 25(11150)/100 = 2787.50
5) Added lines 2 and 4 = 4386+2787.50 = 7173.50
Hence tax amount due by Mary Hernandez = 7173.50 $