You can obtain 16.4 oz cereal for $2.79.
That implies 25oz will cost $x.
If we keep the oz on one side and the $ on the other, we can build an equation to solve for the unknown x.
We start with two expressions that we want to have similar results. These are mathematical expressions of the first two lines we wrote above.
16.4oz -> $2.79
25oz -> $x
To complete the equation we can divide one expression by the other and equate them:
(16.4oz)/(25oz) = ($2.79)/x
(16.4cancel(oz))/(25cancel(oz)) = ($2.79)/x simplify and then cross multiply
16.4x = 25*$2.79
#16.4x = $69.75
x=$4.25
To check the answer for correctness, 25oz is about 1/3 more than 16.4oz. That means if the approximately $3. were also increased by 1/3, we should add about another $1. So the total will be around $4.
Then you would receive $5.00 - $4.25 = $0.75 or 75 cents change from a fiver.
