1. **State the problem:** Calculate the total income tax Mr Simba and his wife pay in one year based on their monthly incomes and given tax rates. 2. **Identify monthly incomes:** Mr Simba's salary = $35000$ Wife's salary = $23000$ 3. **Tax brackets per month:** - First $9000$ taxed at $0\%$ (no tax) - Next $3000$ taxed at $15\%$ - Any amount above $12000$ taxed at $30\%$ 4. **Calculate Mr Simba's monthly tax:** - First $9000$: tax = $0\% \times 9000 = 0$ - Next $3000$: tax = $15\% \times 3000 = 0.15 \times 3000 = 450$ - Remaining amount: $35000 - 9000 - 3000 = 23000$ - Tax on remaining: $30\% \times 23000 = 0.30 \times 23000 = 6900$ - Total tax per month for Mr Simba: $0 + 450 + 6900 = 7350$ 5. **Calculate wife’s monthly tax:** - First $9000$: tax = $0$ - Next $3000$: tax = $450$ (same as above) - Remaining amount: $23000 - 9000 - 3000 = 11000$ - Tax on remaining: $30\% \times 11000 = 0.30 \times 11000 = 3300$ - Total tax per month for wife: $0 + 450 + 3300 = 3750$ 6. **Sum monthly taxes:** Total monthly tax = $7350 + 3750 = 11100$ 7. **Calculate annual tax:** Total annual tax = $11100 \times 12 = 133200$ **Final answer:** They pay a total of **133200** in income tax per year.