The salary of the real estate broker = $18,000
Commission earned on total sales = 4% or 0.04
Total income earnings = $55,000
Let the total sales be = x
Equation becomes :
[tex]18000+0.04x=55000[/tex]
[tex]0.04x=55000-18000[/tex]
[tex]0.04x=37000[/tex]
[tex]x=925000[/tex]
Hence, the real estate broker must sell $925,000 worth of real estate to earn $55,000.