Question 849292
Let width of the pool be x and length of the pool is x+8. 
area of side walk = area of total area - area of the pool
320 = (x+4)(x+8+4) - (x)(x+8)
320 = (x+4)(x+12) - x^2 - 8x
320 = X^2 +4x+12x +48 -x^2-8x
320 = 8x + 48
272 =8x
x= 34
Width of the pool = 34 length = 42

Dimensions of the pool = 42*34.