Let y directly proportional to X
thus y = CX
where c is proportionality constant
given c= 9
thus y = 9x
I think its C cuz it makes more sense then B.
Answer: 13 will be your answer hope this helps
Step-by-step explanation:
The statement that are important when representing functions are:
- It is important to explain what your variable represents and to include units.
- Functions may depend on more than one variable.
<h3>What is are
functions?</h3>
A function can be described as the relation between a set of inputs that have one output each. it help to display the relationship between inputs in a case whereby each input is related to exactly one output.
We can denote the function by f(x) where x is the input.
Learn more about function at:
brainly.com/question/1415456
#SPJ1
Answer: 
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Explanation:
r = number of red pens
4r = cost of buying r red pens
example: if r = 10, then 4r = 4*10 = 40 is the total cost of buying 10 red pens
If John buys r red pens, then he must buy 20-r black pens so that r and 20-r add to 20.
John buys 20-r black pens, and at $5 each, so it will cost 5(20-r) dollars for just the black pens alone.
In total, John spends 4r + 5(20-r) dollars for all the pens (red & black)
We want $92 be the most he spends. This is the ceiling or highest value possible.
Therefore,

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Extra info:
If you want to solve for r, then

distribute

add r to both sides

subtract 92 from both sides


So John must buy at least 8 red pens. The most he can buy is 20 red pens since he wants 20 pens total.