Interesting problem.
First - let's figure cost of each uniform at purchase.
3,000/40 = $75 each
When some uniforms were returned at $40 - there was a difference of $35 in what they paid and what they rec'd in return. ($75 - 35 = $40)
Is there more to this problem? By saying f(4), you'd be inputting a 4 for every variable x. There is not enough info here to answer the question.
F = 18 ft.
The law of cosines states
c² = a² + b² - 2ab cos C
Using our information, we have
c² = 23² + 16² - 2(23)(16)cos 52
c² = 529 + 256 - 736cos 52
c² = 785 - 736cos 52
c² = 331.8732
Taking the square root of both sides, we have
c = √331.8732 = 18.22 ≈ 18
no, this is false. 1 is greater than 12/20.