Using Ratios to Create Proportions

1. 12 pizzas $$\eqalign{\dfrac{2 \text{ pizzas}}{15 \text{ minutes}}&=\dfrac{x \text{ pizzas}}{90 \text{ minutes}}\\15x&=180\\x&=12}$$

2. 15 minutes $$\eqalign{\dfrac{15 \text{ miles}}{25 \text{ minutes}}&=\dfrac{9 \text{ miles}}{x \text{ minutes}}\\15x&=225\\x&=15}$$

3. 45 word problems $$\eqalign{\dfrac{3 \text{ word problems}}{12 \text{ minutes}}&=\dfrac{x \text{ word problems}}{3 \text{ hours}}\\\dfrac{3 \text{ word problems}}{12 \text{ minutes}}&=\dfrac{x \text{ word problems}}{180 \text{ minutes}}\\12x&=540\\x&=45}$$

4. 35 minutes $$\eqalign{\dfrac{4 \text{ miles}}{20 \text{ minutes}}&=\dfrac{7 \text{ miles}}{x \text{ minutes}}\\4x&=140\\x&=35}$$

5. 75 minutes $$\eqalign{\dfrac{2 \text{ miles}}{30 \text{ minutes}}&=\dfrac{5 \text{ miles}}{x \text{ minutes}}\\2x&=150\\x&=75}$$

6. 25 minutes$$\eqalign{\dfrac{6 \text{ miles}}{10 \text{ minutes}}&=\dfrac{15 \text{ miles}}{x \text{ minutes}}\\6x&=150\\x&=25}$$

7. \$.80 $$\eqalign{\dfrac{12 \text{ eggs}}{2.40 \text{ dollars}}&=\dfrac{4 \text{ eggs}}{x \text{ dollars}}\\12x&=9.60\\x&=.8}$$

8. \$.70 $$\eqalign{\dfrac{12 \text{ eggs}}{1.20 \text{ dollars}}&=\dfrac{7 \text{ eggs}}{x \text{ dollars}}\\12x&=8.40\\x&=.7}$$

9. \$.30 $$\eqalign{\dfrac{6 \text{ eggs}}{.60 \text{ dollars}}&=\dfrac{3 \text{ eggs}}{x \text{ dollars}}\\6x&=1.80\\x&=.3}$$

10. \$2.33 $$\eqalign{\dfrac{6 \text{ sodas}}{7 \text{ dollars}}&=\dfrac{2 \text{ sodas}}{x \text{ dollars}}\\6x&=14\\x&=2.33}$$

11. \$.46 $$\eqalign{\dfrac{20 \text{ pencils}}{1.85 \text{ dollars}}&=\dfrac{5 \text{ pencils}}{x \text{ dollars}}\\20x&=9.25\\x&=.4625}$$

12. \$6.25 $$\eqalign{\dfrac{12 \text{ cupcakes}}{15 \text{ dollars}}&=\dfrac{5 \text{ cupcakes}}{x \text{ dollars}}\\12x&=75\\x&=6.25}$$