The number of ounces of cereal in the third box is 32.
<u>Explanation:</u>
Given-
10 oy box = $3
Price of 1 ounce box = $3/10
= $0.3
20 oy box = $5
Price of 1 oy box = $5/20
= $0.25
Therefore, it is beneficial to buy a 20 oy box as it is comparatively cheaper than the 10 oy box.
Third box of cereal = $8
$5 is the price of 20 oy box
$8 will be the price of x oy box
So,
Therefore, the number of ounces of cereal in the third box is 32.