First let find the unit rate which is how much will one ounce cost?
To find the unit rate you have to divide 2.79 divided by 16.4 which gives you .17 .
For ever ouce you buy its going to cost you 17 cents.
you are trying to find how much 25 ounces cost so multiply 25x.17
And you get a result of 4 dollars, the answer is $4