Question

a 10-ounce package of animal cookies costs $2. what should a 25-ounce package cost, assuming the same cost per ounce?
write a proportion to represent the problem.
use a variable, such as z, to represent the unknown quantity.
$\frac{10\text{ ounce(s)}}{2\text{ dollar(s)}} = \frac{25\text{ ounce(s)}}{z\text{ dollar(s)}}$
solve the proportion using the means and extremes method.
$z \cdot 10 = 2 \cdot 25$
$z \cdot 10 = \square$

Explanation:

Step1: Calculate right-hand side product

$2 \cdot 25 = 50$

Step2: Isolate variable z

$z = \frac{50}{10}$

Step3: Solve for z

$z = 5$

Answer:

The 25-ounce package should cost $\$5$. The completed equations are:
Proportion: $\frac{10 \text{ ounce(s)}}{2 \text{ dollar(s)}} = \frac{25 \text{ ounce(s)}}{z \text{ dollar(s)}}$
Means and extremes step: $z \cdot 10 = 50$