Answer:
C
Step-by-step explanation:
$6500 is a one time purchase so there is no variable attached.
$550 and $900 per week is reoccurring so there will be a variable attached.
Since $900 is what she is making each week, this will be separate from her costs (can eliminate D).
To make a profit, her amount earned will need to be greater than her expenses, so the answer is C.
Let's call the width: w
the lenght is then 3w+4 ("4 more than 3 times the width")
and the parameter would be 2(w+3w+4), that is 2*(4w+4), that is 8w+8.
this is also equal to 18.4:
8w+8=18.4
8w=10.4
w=1.3
this is the width, and the lenght is:
4+3*1,3=4+3.9=7.9
and the area is their product:
1.3*7.9=10.27
Answer

Solution
Simplify both sides of the equation.

We are left with d = 4+
Add

Hence, d = 
Remember that cents has a decimal when put in an equation.
250(x + 11) + 250x = 4250
250x + 2750 + 250x = 4250
500x + 2750 = 4250
500x = 1500
x = 3 cents (pencils)
x+11 = 14 cents (pens)
Divide by 6 on both sides to have the variable by itself. the answer is 8.