Given:
pool length : 10 yards
pool width : 8 yards
Area = 10 yds * 8 yds = 80 yd²
(10 + 2x)(8 + 2x) = 120
10(8 + 2x) + 2x(8+2x) = 120
80 + 20x + 16x + 4x² = 120
4x² + 36x + 80 - 120 = 0
4x² + 36x - 40 = 0
4(x² + 9x - 10) = 0
4(x + 10)(x - 1) = 0
x + 10 = 0
x = -10
x - 1 = 0
x = 1
the width of the deck is 1 yard
$7, I think. I would not be too sure about it, though.
The first package is 4 oz (1/4lb) at 79cents = 19.75 cents/oz
Second Package is 8 oz at 1.59 = 19.875 cents / oz
So the first package is cheaper per ounce.