Answer:
C(x) = 
Step-by-step explanation:
Data provided in the question:
Area of the field = 3600 square feet
Fencing charges = $3.50 per foot
Let the side along the river be 'x' feet and the other side of the 'B'
now,
Area of rectangle = Bx = 3600 square feet
or
B =
feet
and total length to be fenced = x + 2B
therefore,
Total cost of fencing = Fencing charges × total length to be fenced
or
Total cost of fencing = $3.50 × ( x + 2B )
substituting the value of B from (1)
Total cost of fencing, C(x) = 
or
C(x) = 
I believe the answer is A
Unknown factor is multiplication and then quotient is division
There are three prime numbers and 3 even numbers on a number cube, so the probability of each is 3/6 = 1/2.