Solve the Problem $\{ x \mid 21 < x < 19 \}$

Multiple Choice

Solve the problem.
-The revenue achieved by selling x graphing calculators is figured to be x(39 - 0.2x) dollars. The cost of each calculator is $27. How many graphing calculators must be sold to make a profit (revenue - cost) of at least
$160.00?

A) $\{ x \mid 21 < x < 19 \}$
B) $\{ x \mid 5 < x < 25 \}$
C) $\{ x \mid 20 < x < 40 \}$
D) $\{ x \mid 22 < x < 38 \}$