Answer: The required equation is,

Explanation:
Let x be the size of the larger bottle,
Since, the size of smaller bottle of lotion = 5.4 ounces,
According to the question,
The larger bottle gives 20% more free lotion,
The size of the larger bottle = The size of smaller bottle of lotion + 20 % of the size of smaller bottle of lotion
= 120 % of the size of smaller bottle of lotion
= 120 % of 5.4


Which is the required equation that could be used to find the size of the larger bottle.