Georgia Milestones Grades 6-8 Ratios and Proportional Relationships. Practice it free.

Use a conversion factor with pounds in the numerator so stones cancel: $28 \text{ stones} \times \dfrac{14 \text{ lb}}{1 \text{ stone}} = 392 \text{ lb}$.

Five gallons of water is $5 \times 16 = 80$ cups. With a $9$ to $72$ ratio, $\dfrac{9}{72} = \dfrac{x}{80}$, so $72x = 720$ and $x = 10$ cups of concentrate.

Multiply by 100: $0.04 \times 100 = 4\%$.

Discount: $\dfrac{20}{100} \times \text{\char36}40 = \text{\char36}8\textsf{.}$ Sale price: $\text{\char36}40 - \text{\char36}8 = \text{\char36}32\textsf{.}$

$\dfrac{50}{200} = 0.25 = 25\%\textsf{.}$

Convert $35\%$ to a decimal and multiply: $0.35 \times 160 = 56$ boxes.

$50\% = 0.5\textsf{.}$ Then $0.5 \times 30 = 15\textsf{.}$

$\frac{4}{40} = 0.1 = 10\%$.