Let x be the length of the brick side (and one fenced side)
Let y be the width of the other two sides.
Then we have
xy = 950
The cost c is then
c = 10x + 5(x+2y) = 15x + 10y = 15x + 9500/x
dc/dx = 15 - 9500/x^2
So, find x where dc/dx = 0
ABC Daycare wants to build a fence to enclose a rectangular playground. The area of the playground is 950 square feet. The fence along three of the sides costs $5 per foot and the fence along the fourth side, which will be made of brick, costs $10 per foot. Find the length of the brick fence that will minimize the cost of enclosing the playground. (Round your answer to one decimal place.)
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