Answer:
Buy the two 12 ounce packages with double 50 cent coupons.
Explanation:
The 12 ounce package is 2.98. The store doubles coupons, so that 50 cent coupon becomes $1.00 off. So the 12 ounce pkg is $1.98.
$1.98/12 = 0.165 or 16.5 cents per ounce
If you buy 2 pkgs, it's 1.98 x 2 = $3.96. (Note that we already know that the 2 pkgs of 12 ounce using the coupon is less than the 24 ounce package at $3.98.)
The 24 ounce pkg is $3.98.
$3.98/24 = 0.16583333333 so it's slightly more expensive.