AK STAR Grades 6-8 Ratio & Proportion. Practice it free.

Use a conversion factor with liters in the numerator so milliliters cancel: $2{,}500 \text{ mL} \times \dfrac{1 \text{ L}}{1{,}000 \text{ mL}} = 2.5 \text{ L}$.

Six gallons of water is $6 \times 16 = 96$ cups. With a $5$ to $40$ ratio, $\dfrac{5}{40} = \dfrac{x}{96}$, so $40x = 480$ and $x = 12$ cups of concentrate.

Divide by 100: $5\% = 0.05$.

Discount: $\dfrac{15}{100} \times \text{\char36}120 = \text{\char36}18\textsf{.}$ Sale price: $\text{\char36}120 - \text{\char36}18 = \text{\char36}102\textsf{.}$

$\dfrac{48}{160} = 0.3 = 30\%\textsf{.}$

Convert $15\%$ to a decimal and multiply: $0.15 \times 1{,}200 = 180$ pages.

$25\% = 0.25\textsf{.}$ Then $0.25 \times 70 = 17.5\textsf{.}$

Discount: $0.15 \times \text{\char36}60 = \text{\char36}9.0$. Sale: $\text{\char36}60 - \text{\char36}9.0 = \text{\char36}51.0$.