The monthly salary S of a shop assistant is the sum of a fixed salary of $500 plus 5% of all monthly sales. What should the monthly sales be so that her monthly salary reaches $1500?  Choose the correct choice from the following answers: A) $50000 B) $40000 C) $30000 D) $20000 E) None of these
Let S be the total monthly salary and x be the monthly sales, hence   S = 500 + 5% * x   Find sales x so that S = 1500, hence   1500 = 500 + 5% * x = 500 + 0.05 x   Solve for x   x = (1500 - 500) / 0.05= 
<gadget id="calculator">(1500 - 500) / 0.05</gadget>
<output>20_000</output>
$20000   Answer $20000
<result>D</result>
The monthly salary S of a shop assistant is the sum of a fixed salary of $500 plus 5% of all monthly sales. What should the monthly sales be so that her monthly salary reaches $1500?