MO MAP Grades 6-8 Ratios and Proportional Relationships. Practice it free.

Two quarts of water is $2 \times 4 = 8$ cups. With a $6$ to $24$ ratio, $\dfrac{6}{24} = \dfrac{x}{8}$, so $24x = 48$ and $x = 2$ cups of concentrate.

Set up a proportion: $\dfrac{3}{18} = \dfrac{x}{30}$, so $18x = 90$ and $x = 5$ cups.

$\dfrac{x}{y} = \dfrac{8}{3}$. With $y = 45$, $\dfrac{x}{45} = \dfrac{8}{3}$, so $3x = 360$ and $x = 120$.

Discount: $\dfrac{25}{100} \times \text{\char36}100 = \text{\char36}25\textsf{.}$ Sale price: $\text{\char36}100 - \text{\char36}25 = \text{\char36}75\textsf{.}$

Convert: $30\% = 0.3$. Then $0.3 \times 90 = 27$.

The sale price is $75\%$ of the original: $0.75p = 45$, so $p = 45 \div 0.75 = 60$ dollars.

Tax: $\dfrac{6}{100} \times \text{\char36}200 = \text{\char36}12\textsf{.}$

Tip: $\dfrac{10}{100} \times \text{\char36}60 = \text{\char36}6\textsf{.}$