Step-by-step explanation: The answer is 105 square feet because find the area of the pool by multiplying 12 and 20 to get 240. You then want to find the area of the total space. Add 3 to 12 and add 3 to 20. Then multiply 23 by 15 to get 345. You then want to subtract 345 - 240 to get rid of the extra space to get your answer of 105.
