Answer:
72 ft
Explanation:
The perimeter of the concrete walk is the sum of the lengths of its outside edges. Each of those is two border-widths longer than the parallel pool dimension.
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The border width is ...
(10 ft) + 2(3 ft) = 16 ft
The border length is ...
(14 ft) + 2(3 ft) = 20 ft
The perimeter is the sum of the lengths of the four sides. It can be found using the formula ...
P = 2(L +W)
P = 2(20 ft + 16 ft) = 2(36 ft) = 72 ft
The perimeter of the concrete walk is 72 feet.
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Additional comment
The term "perimeter of the concrete walk" is actually somewhat ambiguous. It could refer to the total length of all of the edges of the concrete walk. If that is the case, then the 48 foot length of the inside edge must be added to the length of the outside edge for a total of 120 feet. That is, if one were to mark the edges of the walk with tape, for example, 120 feet of tape would be needed.