Comment
I'm taking this to mean that he does not have to sell above 7000 to start getting a commission. Furthermore, he makes 6% on the full 55000.
Formula
T = Base Salary + 6% Total Sales
T = Take home salary
Base Salary = 7000
Total Sales = 55000
Substitute and Solve
T = 7000 + 6% * 55000 Change the % to a decimal
T = 7000 + 6/100 * 55000
T = 7000 + 0.06 * 55000
T = 7000 + 3300
T = 10300 dollars.
Conclusion
His take home salary = 10300 dollars <<<< answer.