Solve the Problem $x$ Graphing Calculators Is Figured to Be $x ( 28 - 0.2 x )$

Multiple Choice

Solve the problem.
-The revenue achieved by selling $x$ graphing calculators is figured to be $x ( 28 - 0.2 x )$ dollars. The cost of each calculator is $\$ 20$ . How many graphing calculators must be sold to make a profit (revenue - cost) of at least $\$ 75.00 ?$

A) $\{ x \mid 17 < x < 23 \}$
B) $\{ x \mid 16 < \mathrm { x } < 14 \}$
C) $\{ x b 5 < x < 15 \}$
D) $\{ x \mid 15 < x < 25 \}$