Answer:
If the new cereal box contains 20% more than the original cereal box, then the original cereal box contained 100% - 20% = 80% of the new cereal box.
Let X be the original cereal box amount in ounces, then we can set up the following equation:
X + 0.20X = 18.48
Simplifying and solving for X:
1.20X = 18.48
X = 15.40
Therefore, the original cereal box amount was 15.40 ounces.